How to Remove Coliform Bacteria from Well Water (Treatment Guide)
Well Water Bacteria Treatment
How to Remove Coliform Bacteria from Well Water (Treatment Guide)
Your well water just tested positive for coliform bacteria. That is a serious result, and you are right to be concerned. This guide walks you through exactly what to do: the immediate safety steps to protect your family today, how to disinfect your well short-term, and the long-term treatment system that prevents bacteria from ever reaching your faucets again.
This article is part of our well water treatment library. For a broader overview of UV disinfection technology, see our UV Water Disinfection Systems.
If Your Water Just Tested Positive
Stop drinking your well water immediately. Use bottled water or boil your water at a rolling boil for at least one full minute before drinking, cooking, brushing teeth, or making ice. This applies to everyone in the household, but especially to infants, elderly family members, pregnant women, and anyone with a weakened immune system. Continue reading for the full action plan.
The Short Version
A positive coliform test means your well water has a pathway for contamination. Here is the correct response:
- Right now: Stop drinking the water. Boil or use bottled water for all consumption. This is non-negotiable until the problem is resolved.
- Within 48 hours: Shock chlorinate your well with household bleach to kill existing bacteria. Retest 7 to 10 days later.
- Long-term fix: Install a UV disinfection system to continuously kill 99.99% of bacteria, viruses, and pathogens at the point of entry. This is the only permanent solution for recurring coliform.
- If E. coli was detected: This indicates fecal contamination. The urgency is higher. Do not use the water for any purpose until the source is identified and eliminated. Contact your local health department.
What Should You Do Right Now?
Answer two quick questions based on your test results.
What did your water test detect?
Check your lab report for the specific bacteria identified.
Is this the first time your well tested positive?
Recurring positives require a different approach than a one-time result.
Do you know the source of contamination?
E. coli means fecal matter has entered your well. The source matters.
Your action plan:
1. Stop drinking the water until resolved. Boil or use bottled.
2. Inspect your well cap, casing, and seal for cracks or gaps.
3. Shock chlorinate your well (see instructions below).
4. Retest 7 to 10 days after chlorination.
5. If the retest is negative, your well is likely fine. If positive again, you need a permanent UV system.
Important: Even a single positive test means your well is vulnerable to surface contamination. A UV system provides permanent protection.
Your action plan:
1. Continue using bottled or boiled water.
2. Have your well inspected by a licensed well driller for casing damage, a damaged well cap, or surface water intrusion.
3. Fix any well integrity issues found.
4. Install a UV disinfection system as your last line of defense before water enters your home.
5. Retest after the UV system is operational.
What Aidan typically recommends: The Viqua VH410 UV System ($995) provides continuous 99.99% bacteria elimination with high flow rates for a whole house.
Your immediate action plan:
1. Do not use the water at all for drinking, cooking, brushing teeth, or making ice.
2. Contact your local health department for guidance specific to your area.
3. Have a licensed well driller and septic professional inspect your property to locate the contamination source.
4. Shock chlorinate the well after the source is identified and fixed.
5. Retest 7 to 10 days later. A UV system is strongly recommended even after the source is fixed.
Why this is urgent: According to the CDC, E. coli O157:H7 can cause severe stomach cramps, bloody diarrhea, and in rare cases kidney failure, particularly in children and the elderly.
Your action plan:
1. Fix the identified issue (septic repair, well cap replacement, grading changes, etc.).
2. Shock chlorinate the well after repairs are complete.
3. Wait 7 to 10 days and retest.
4. Install a UV disinfection system as permanent insurance against recontamination.
5. Send your water test to Aidan at 800-460-5810 for a personalized system recommendation based on your full water chemistry.
Note: Many homeowners also have low pH, iron, or hardness issues alongside bacteria. Aidan can design a complete treatment sequence that handles everything in the right order.
Next steps:
1. If you have not tested yet: contact a certified lab in your state or purchase a mail-in test kit that specifically tests for total coliform and E. coli.
2. If you have results but cannot interpret them: take a photo and send it to Aidan at 800-460-5810 (call or text). He reviews water tests every day and can tell you exactly what the numbers mean.
3. While waiting: use bottled or boiled water as a precaution.
Important: Home test strips for bacteria are unreliable. A certified lab test is the only way to get accurate coliform and E. coli results.
What Your Coliform Test Result Actually Means
A positive coliform test does not necessarily mean your water will make you sick today. But it does mean something important: your well has a pathway for contamination, and that pathway needs to be closed.
Coliform bacteria are a large group of organisms found naturally in soil, vegetation, and the intestines of warm-blooded animals. Most coliform species are harmless on their own. The reason labs test for them is that they serve as indicator organisms. According to the EPA, the presence of coliform bacteria in a water supply suggests that disease-causing organisms (pathogens) could also be present through the same contamination pathway.
Think of it this way: coliform bacteria are the canary in the coal mine. Finding them in your well water means the protective barrier between your water supply and the surface environment has been compromised. For more on why private wells are uniquely at risk, see our UV Water Filter for Well Water guide.
The Three Types of Coliform on Your Lab Report
Your lab report may reference one or more of these categories. Understanding which one was detected determines how urgently you need to act:
Total coliform is the broadest category. It includes bacteria found in soil, surface water, and animal intestines. A positive total coliform result (with a negative E. coli result) means contamination is present, but it may not be from fecal sources. Common causes include a cracked well cap, surface water intrusion after heavy rain, or recent well work that introduced bacteria. The EPA Maximum Contaminant Level Goal (MCLG) for total coliform in drinking water is zero.
E. coli (Escherichia coli) is a specific type of coliform that lives exclusively in the intestines of humans and animals. If your test is positive for E. coli, there is fecal contamination in your water. This is a more serious result. Possible sources include a leaking septic system, animal waste entering the well, or damaged well casing that allows surface runoff to reach groundwater. The CDC identifies certain strains of E. coli (such as O157:H7) as capable of causing severe illness including bloody diarrhea, stomach cramps, and kidney failure in vulnerable populations.
Fecal coliform is an older testing category that overlaps with E. coli. Some labs still report it. A positive fecal coliform result has the same implications as a positive E. coli result: fecal contamination is present, and the health risk is elevated.
Risk Levels: Total Coliform vs. E. coli vs. Fecal Coliform
| Test Result | What It Means | Health Risk | Response Urgency |
|---|---|---|---|
| Total coliform positive, E. coli negative | Your well is vulnerable to surface contamination, but no fecal source detected | Low to moderate | Stop drinking. Shock chlorinate within 48 hours. Retest in 7 to 10 days. |
| Total coliform positive, E. coli positive | Fecal contamination confirmed. Septic failure, animal waste, or surface runoff is entering your well. | High | Stop all water use for consumption. Contact health department. Identify and fix the source before chlorinating. |
| Fecal coliform positive | Same implications as E. coli positive | High | Same as E. coli positive above |
| Any positive result with GI symptoms in household | Possible active waterborne illness | Urgent | Seek medical attention. Report to your local health department. |
A Common Misconception
Some homeowners assume that because they have been drinking their well water for years without getting sick, a positive coliform test is not a real concern. This is dangerous thinking. Bacteria levels fluctuate seasonally. A well that tests clean in winter may test positive after spring rains. And some waterborne pathogens cause chronic low-grade symptoms (fatigue, digestive issues) that people attribute to other causes. The EPA standard exists for a reason: the acceptable level of coliform bacteria in drinking water is zero.
Immediate Steps (Do This Today)
The moment you receive a positive coliform result, follow this action plan. These steps are adapted from EPA and CDC guidelines for private well owners.
Stop Drinking the Water
Switch to bottled water or boil your well water at a rolling boil for at least one full minute (three minutes above 6,500 feet elevation). Use boiled or bottled water for drinking, cooking, brushing teeth, making ice, and preparing baby formula. According to the PA Department of Health, water containing coliform bacteria can still be used for showering and laundry as long as it is not swallowed.
Notify Your Household
Make sure every person in the home knows not to drink the tap water. Post a note on the kitchen sink. If you have young children, elderly family members, or anyone with a compromised immune system, the risk is higher for these groups.
Inspect Your Well
Check the well cap or cover for cracks, gaps, or damage. Look for standing water around the wellhead. Verify that the ground slopes away from the well casing (not toward it). Check for any nearby sources of contamination: septic tanks (should be at least 50 feet from the well per most state codes), animal enclosures, chemical storage, or areas where runoff collects.
Shock Chlorinate the Well
This is the standard first response for a positive coliform test. It kills existing bacteria inside the well, the plumbing, and the pressure tank. See the detailed procedure below.
Retest Your Water
Collect a new sample and send it to a certified lab. Do not use a home test kit for this step. If the retest comes back negative, your well may have cleared the contamination. If it comes back positive again, shock chlorination alone is not enough, and you need a permanent treatment solution.
Install a UV Disinfection System
A UV system mounted at your point of entry eliminates 99.99% of bacteria, viruses, and protozoa without chemicals. This is the same technology used in municipal water treatment plants. See the long-term solution section for details.
Short-Term Fix: How to Shock Chlorinate Your Well
Shock chlorination (also called well disinfection) uses a high concentration of chlorine bleach to kill bacteria throughout your entire well system. It is the standard first-response treatment recommended by the EPA, state health departments, and well drilling associations.
However, it is important to understand what shock chlorination is and what it is not. It kills the bacteria that are present at the time of treatment. It does not prevent new bacteria from entering the well. If your well has a structural vulnerability (cracked casing, damaged cap, shallow depth, or proximity to a contamination source), bacteria will return after the chlorine dissipates.
"We had coliform in our water tests. We ended up chlorinating our water supply three times but it was still there. We read up on coliform and when it's in your water, that means there are pathogens in your water that cause disease."
Lois Heath, verified MAW customerShock Chlorination Procedure
What you need: unscented household bleach (5.25% to 8.25% sodium hypochlorite), a clean 5-gallon bucket, a garden hose, and rubber gloves.
- Turn off power to the well pump. Open the well cap or well seal. If your well cap is locked or you are not comfortable opening it, contact a licensed well driller.
- Calculate the amount of bleach. For a standard 6-inch diameter residential well, use approximately 3 cups of household bleach per 100 feet of water depth. For a 4-inch well, use about 1.5 cups per 100 feet. If you do not know your well depth, your well driller's records, your property deed, or your state's well log database may have it. When in doubt, use more bleach rather than less.
- Mix the bleach with water. Pour the measured bleach into a 5-gallon bucket and fill with water. Pour this solution directly into the well casing.
- Circulate the chlorinated water. Connect a garden hose to an outdoor faucet and run it back into the well casing for 15 to 20 minutes. This circulates chlorinated water throughout the well and mixes it thoroughly.
- Run every faucet inside the house (hot and cold) until you smell chlorine at each one. This ensures the chlorine reaches all plumbing, the pressure tank, and the water heater. Then shut them all off.
- Let it sit for 12 to 24 hours. Do not use any water during this time. Do not run the dishwasher, washing machine, or flush toilets. The chlorine needs contact time to kill bacteria.
- Flush the system. After 12 to 24 hours, run an outdoor hose (away from your septic system, garden, and waterways) until the chlorine smell is gone. Then run each indoor faucet until the smell clears.
- Wait 7 to 10 days and retest. Do not test immediately after chlorination because residual chlorine will kill bacteria in the sample and give a false negative. The waiting period allows any surviving bacteria to repopulate to detectable levels.
Protect Your Water Treatment Equipment
If you have existing water treatment equipment (water softener, acid neutralizer, iron filter, carbon filter, or UV system), bypass all of it before shock chlorinating. High concentrations of chlorine will damage water softener resin, carbon media, and UV system components. Run the chlorinated water only through your raw plumbing. After flushing is complete and chlorine levels are undetectable, put your equipment back in service.
If Shock Chlorination Fails
If your water tests positive again after shock chlorination, do not simply chlorinate a second or third time and hope for a different result. Recurring coliform after shock chlorination means one of two things: (1) your well has a structural problem that allows ongoing contamination, or (2) bacteria have colonized the well casing, pipes, or pressure tank biofilm to the point where a single chlorination cannot eliminate them. Either way, you need a permanent UV disinfection system and likely a well inspection by a licensed driller. Call Aidan at 800-460-5810 to discuss your situation.
Long-Term Solution: UV Disinfection
Ultraviolet (UV) disinfection is the only practical long-term solution for recurring coliform bacteria in a private well. It works by exposing water to UV-C light at 254 nanometers, which destroys the DNA of bacteria, viruses, and protozoa, preventing them from reproducing or causing infection. The EPA, CDC, and NSF all recognize UV disinfection as an effective treatment for microbiological contaminants in drinking water. For a deep dive into how UV technology works, pre-treatment requirements, and maintenance, see our Complete Guide to UV Water Disinfection.
A whole-house UV system installs at the point of entry (where the water line enters your home, after any other filtration equipment) and treats every drop of water before it reaches a single faucet, shower, or appliance. There are no chemicals added to the water, no taste or odor changes, and no waste water produced.
How UV Compares to Other Bacteria Treatment Methods
Shock Chlorination
Kills existing bacteria but does not prevent recontamination. Effectiveness lasts only until new bacteria enter the well. Cannot run continuously. Useful as a first response, not a permanent solution.
Continuous Chlorination (Chemical Feed System)
Injects chlorine continuously using a chemical feed pump. Effective at killing bacteria, but requires regular chemical purchases, pump maintenance, and a retention tank for contact time. Also requires a carbon filter downstream to remove chlorine taste and byproducts. More complex and more expensive to maintain than UV. For a complete side-by-side analysis, see our UV Disinfection vs Chlorination comparison.
UV Disinfection System
Continuously kills 99.99% of bacteria, viruses, and protozoa without chemicals. No taste change, no waste water, no ongoing chemical cost. Only maintenance is an annual bulb replacement. Industry standard for private well water disinfection. NSF/ANSI 55 Class A certified systems are rated for disinfection of microbiologically unsafe water.
Reverse Osmosis (RO)
An RO system at the kitchen sink can remove bacteria from drinking water, but it only treats one faucet. It does not protect showers, washing machines, dishwashers, or any other water use in the home. Not a whole-house solution.
What Aidan Recommends
After 32 years of installing water treatment systems, the UV system I recommend most for coliform treatment is the Viqua VH410. It handles flow rates up to 18 gallons per minute, which is more than enough for most homes, and it is NSF/ANSI 55 Class A certified for disinfection of microbiologically unsafe water.
For smaller households (1 to 2 bathrooms), the Viqua VH200 at 9 GPM is a solid choice and costs $895. For help choosing between models, see our 2026 UV Water Purifier Buyer's Guide.
| System | Flow Rate | Best For | Price | Annual Bulb Cost |
|---|---|---|---|---|
| Viqua VH200 | 9 GPM | 1-2 bathrooms | $895 | $145 |
| Viqua VH410 | 18 GPM | 3+ bathrooms | $995 | $160 |
"We found out our well water tested positive for bacteria. As soon as we found out, we knew it was imperative for our families safety that we treated our water. We purchased this water sanitizer kit. We were a little apprehensive about it at first, but we decided we would give it a shot."
Arnold Wade, verified MAW customer"Had it installed by local plumber. Working awesome and our water is free of coliform and every other bacteria. Saved hundreds over Home Depot, Lowes and the local plumbing houses."
Steve Carroll, verified MAW customerWhat UV Maintenance Looks Like
UV systems are about as low-maintenance as water treatment gets. Replace the UV bulb once every 12 months (it takes about 10 minutes). The quartz sleeve that protects the bulb should be cleaned or replaced every 1 to 2 years depending on your water quality. That is the entire maintenance schedule. No chemicals to buy, no media to replenish, no backwash cycles to manage.
Where UV Fits in Your Treatment System
This is one of the most important details that government websites leave out. A UV system must be installed in the correct position in your treatment sequence, and the water entering the UV chamber must meet certain quality requirements. If you skip this step, the UV system will not perform correctly.
The water must be clear, soft, and iron-free before it reaches the UV light. Iron, sediment, hardness, and tannins can coat the quartz sleeve or create shadows in the water that allow bacteria to pass through untreated. This is why Aidan always designs a complete treatment sequence, not just a single piece of equipment.
Correct Installation Order
The UV system always goes last, right before the water enters your home plumbing. This ensures that bacteria cannot reenter the water between the UV treatment and your faucets. It also ensures the water reaching the UV chamber has already been cleaned of particles and minerals that would reduce UV effectiveness.
Why Treatment Order Matters
If you put the UV light before your iron filter or softener, iron and mineral deposits will cloud the quartz sleeve within weeks, drastically reducing UV intensity. On a call with a homeowner recently, Aidan explained it clearly: "You have to clean all the iron up out of the water before it goes into the UV light. It'll cloud the crystal, and it won't be effective." Treat the water quality issues first, then disinfect last.
Many of the customers who contact us about coliform also have other water quality issues: low pH, iron, hardness, or sulfur. That is completely normal for well water. A homeowner in Virginia recently reached out after her well required bleaching due to coliform during a home purchase. Aidan reviewed her water test and recommended an iron filter, a water softener, and a Viqua VH410 UV system in that order. The system addresses every issue in the correct sequence.
If you are not sure what else is in your water beyond bacteria, call Aidan at 800-460-5810 or text a photo of your water test. He reviews water tests every day and will design a treatment sequence tailored to your specific water chemistry.
When and How to Retest
Testing is how you confirm your treatment is working. Do not assume the problem is solved just because you shock chlorinated or installed a UV system. Verify with data.
Retesting Schedule
- 7 to 10 days after shock chlorination: Collect a sample and submit to a certified lab. Testing too early (within the first 5 days) can give a false negative because residual chlorine may still be present in the system.
- After installing a UV system: Test the water after the UV system has been running for at least 48 hours. This confirms the system is performing correctly.
- Annually: The EPA recommends testing private well water for coliform bacteria at least once per year, even if no problems are suspected.
- After any well work: Anytime a plumber, well driller, or anyone else opens the well or works on the pressure tank, test for coliform 7 to 10 days later.
- After flooding or heavy storm events: If your well area experienced flooding, standing water near the wellhead, or unusually heavy rain, retest.
How to Collect a Proper Sample
Incorrect sampling technique is one of the most common reasons for false positive coliform results. Follow these steps to avoid contaminating the sample:
- Use a sterile sample bottle provided by the lab. Do not use a household container.
- Remove the aerator from the faucet (the screen at the tip). Aerators harbor bacteria and can contaminate the sample.
- Run the cold water for 2 to 3 minutes before collecting. This flushes standing water from the pipes.
- Open the sterile bottle carefully. Do not touch the inside of the cap or the bottle opening.
- Fill the bottle and cap it immediately.
- Keep the sample cold (not frozen) and deliver it to the lab within 24 hours, preferably within 6 hours.
Use a state-certified lab, not a home test kit. Home test kits for bacteria (the ones with color-changing vials) have high false-positive and false-negative rates. A certified lab test typically costs $20 to $50 and gives you reliable, quantitative results.
Preventing Recontamination
Shock chlorination and UV treatment address the bacteria themselves, but preventing recontamination means addressing the pathway that let bacteria enter in the first place.
Well Integrity Checklist
- Well cap: Must be a sanitary, vermin-proof cap that sits tightly on the casing. Replace if cracked, loose, or corroded. Insects and small animals entering through a damaged cap are a surprisingly common contamination source.
- Well casing: Should extend at least 12 inches above the ground surface (some states require more). Check for cracks, corrosion holes, or gaps. If the casing is damaged below grade, a licensed well driller is needed for repair or replacement.
- Grading: The ground around the wellhead should slope away in all directions. Standing water near the well casing allows surface water (carrying bacteria) to seep down alongside the casing into the aquifer.
- Septic system distance: Most state codes require a minimum of 50 feet between the well and the septic tank, and 100 feet from the septic drain field. If your well is too close to the septic system, structural fixes or a new well location may be necessary.
- Animal access: Keep livestock, poultry, and pet waste away from the wellhead area. Fence the well area if needed.
- Well depth: Shallow wells (under 50 feet) are significantly more vulnerable to surface contamination than deeper wells. If you have a shallow well with recurring bacteria issues, deepening or replacing the well may be the only permanent fix.
Annual Maintenance
- Test for coliform and E. coli annually (EPA recommendation for all private wells)
- Replace UV bulb every 12 months, regardless of whether the light still appears to be working (UV output degrades over time even when the bulb looks fine)
- Inspect the well cap and casing visually at least once a year
- After any flooding or major storm event, retest within 7 to 10 days
- Keep records of all water tests and well maintenance
For information about a related but different type of bacterial contamination, see our guide to iron bacteria in well water. Iron bacteria create slimy buildup in pipes and wells but are a nuisance problem rather than a health risk.
About the Author: This guide was written by Aidan Walsh, owner of Mid Atlantic Water, with over 32 years of experience in residential water treatment. Aidan has personally designed treatment systems for thousands of homeowners dealing with coliform and E. coli contamination in their well water. Have a question about your water test results? Call Aidan directly at 800-460-5810. He answers the phone himself, seven days a week.
Frequently Asked Questions
Can I shower if my well water tested positive for coliform?
Generally, yes. According to the Pennsylvania Department of Health and other state agencies, water containing total coliform (without E. coli) can be used for showering and bathing as long as you do not swallow it. After showering, wash your hands with soap and safe water. However, if E. coli or fecal coliform is detected, limit all contact and consult your local health department for guidance. For infants, elderly, or immunocompromised household members, use extra caution with any positive result.
Is it common to have coliform bacteria in well water?
Yes, it is relatively common. Studies by the U.S. Geological Survey (USGS) have found that approximately 34% of private wells in the United States test positive for total coliform at some point. It is more common in shallow wells, older wells, and wells in areas with agricultural activity. Being common does not make it acceptable. The EPA MCL for total coliform in drinking water is zero, and every positive result should be addressed.
Will shocking my well get rid of coliform permanently?
Sometimes, but often not. Shock chlorination kills the bacteria present at the time of treatment, but it does not prevent new bacteria from entering. If the contamination was caused by a one-time event (like recent well work or a heavy rainstorm), shock chlorination may be all you need. But if the contamination source is ongoing (cracked casing, nearby septic, shallow well), bacteria will return. One of our customers chlorinated her well three times with the coliform coming back each time before switching to a UV system. If shock chlorination fails once, do not keep repeating it.
My well tested positive for total coliform but negative for E. coli. Should I worry?
You should take it seriously but not panic. A total coliform positive with an E. coli negative means your well has a contamination pathway (bacteria are getting in from the surface), but there is no evidence of fecal contamination. The standard response is to shock chlorinate and retest in 7 to 10 days. If the retest is negative, the issue may have been temporary. If it comes back positive again, a UV disinfection system is the recommended permanent solution. Either way, inspect your well cap, casing, and the area around the wellhead for potential entry points.
What causes coliform bacteria in well water?
The most common causes are: (1) a damaged or improperly sealed well cap that allows insects, surface water, or debris to enter, (2) cracks or corrosion in the well casing, (3) surface water infiltration during heavy rain or flooding, (4) proximity to a septic system, especially a failing one, (5) shallow well depth that does not provide enough natural filtration, (6) recent well work or pump repair that introduced bacteria, and (7) inadequate grouting around the well casing that allows surface water to travel down the outside of the casing into the aquifer.
How much does it cost to treat coliform in well water?
Shock chlorination costs very little (a few dollars in bleach) but is only a temporary fix. For permanent UV disinfection, a whole-house system ranges from $895 for the Viqua VH200 (9 GPM, suitable for smaller homes) to $995 for the Viqua VH410 (18 GPM, suitable for larger homes). Annual maintenance cost is $145 to $160 for a replacement bulb. Most homeowners can install a UV system themselves with basic plumbing skills, avoiding professional installation fees of $200 to $500. Compared to the health risks and the ongoing hassle of repeated shock chlorination, a UV system is one of the best investments a well owner can make.
Can a water filter remove coliform bacteria?
Standard sediment filters and carbon filters do not remove bacteria. Their pore sizes are too large. Certain specialized filters (ceramic filters rated at 0.2 microns, ultrafiltration membranes, and reverse osmosis systems) can physically remove bacteria, but these are typically point-of-use solutions that protect a single faucet. For whole-house bacteria treatment on well water, UV disinfection is the industry standard. It does not filter bacteria; it destroys them by damaging their DNA so they cannot reproduce or cause illness.
What are the symptoms of drinking water with coliform bacteria?
Most total coliform bacteria are harmless to healthy adults and may cause no symptoms at all. However, the concern is what else may be in the water alongside them. If pathogenic organisms (like E. coli O157:H7 or Cryptosporidium) are present, symptoms can include nausea, vomiting, diarrhea, stomach cramps, and fever. According to the CDC, these symptoms typically appear within 1 to 10 days of exposure. Young children, the elderly, pregnant women, and immunocompromised individuals are at significantly higher risk of severe illness. If anyone in your household develops gastrointestinal symptoms and your well water is known to be contaminated, seek medical attention and inform the doctor about your water test results.
Do I need to treat coliform if my well water is also acidic or has iron?
Yes, but the treatment order matters. Acidic water (low pH) and iron in well water need to be corrected before the water reaches the UV system. The typical sequence is: sediment pre-filter, then acid neutralizer (if pH is below 7), then iron filter or water softener, then the UV system last. This ensures the water is clean and clear before UV treatment, which is essential for the UV light to work effectively. Call Aidan at 800-460-5810 with your full water test and he will design the correct treatment sequence for your situation.