How To Fix Acidic Well Water?
How to Fix Acidic Well Water (Low pH): Step-by-Step + Best Treatment Options
Updated: January 21, 2026
To fix acidic (low pH) well water, raise the pH at the point where water enters your home using a whole-home acid neutralizer. Use Calcite when pH is around 6.0 or higher, and use a Calcite + Corosex (FloMag) blend when pH is below ~6.0. If pH is extremely low (often below ~5.3), a soda ash injection system may be more reliable.
Short Video: What is Acid Water?
Quick check: is your well water acidic?
- pH below 7.0 is acidic. In private wells, below ~6.5 is a common corrosion risk zone.
- Common signs: metallic taste, blue-green stains (often copper), pinhole leaks, shortened water heater life.
Important: low pH itself is usually not the direct “health problem.” The bigger concern is that corrosive water can dissolve metals like copper or lead from plumbing and fixtures.
Why low pH matters (corrosion, metals, plumbing damage)
- Corrosion: acidic water attacks metal plumbing, fixtures, and appliances.
- Metal leaching: corrosion can increase dissolved copper and lead at the tap.
- Cost: leaks, premature water heater failure, and repeated plumbing repairs add up fast.
The EPA’s secondary guidance commonly references a pH range of 6.5 to 8.5 to reduce nuisance issues like corrosion and metallic taste (note: private wells are not regulated the same way as public water systems).
Step 1: Test the right things (not just pH)
Minimum tests
- pH (field test or lab)
- Alkalinity (helps predict how “buffered” your water is)
- Hardness (neutralizers often raise hardness)
Strongly recommended if pH is low
- Copper and lead at the tap (especially if you see blue-green staining or have older plumbing)
- Saturation index (often LSI) if your lab reports it, because it can estimate corrosivity better than pH alone
Tip: if your lab provides LSI or similar stability indices, use them. pH is the main driver, but temperature, alkalinity, and hardness also influence corrosion potential.
Step 2: Choose the right fix (decision table)
| Your pH (rule of thumb) | Best whole-home solution | Why it works | What to watch for |
|---|---|---|---|
| ~6.0 to 6.9 (mild to moderate) | Acid neutralizer with Calcite | Calcite dissolves slowly and raises pH while increasing alkalinity. | May increase hardness. Consider a softener if scale becomes an issue. |
| Below ~6.0 (more aggressive acidity) | Acid neutralizer with Calcite + Corosex (FloMag) blend | Magnesium oxide is more reactive for stronger pH correction. | Can raise pH faster, so verify pH after install to avoid overcorrection and scale. |
| Very low pH (often below ~5.3) | Soda ash injection (chemical feed) system | More controllable and effective when acidity is extreme. | More maintenance: solution mixing, pump calibration, ongoing monitoring. |
Option A: Neutralizing filter (preferred in most homes)
- What it is: a corrosion-resistant tank filled with calcite, or calcite + magnesium oxide, installed where water enters the house.
- Best for: most low pH well water scenarios where you want a simpler, low-hassle whole-home fix.
- Real-world side effect: neutralizers often add minerals back in, which can increase hardness and scale risk.
Shop neutralizers here: whole-home acid neutralizers.
Option B: Soda ash injection system
- What it is: a metering pump injects an alkaline solution (soda ash) to raise pH.
- Best for: very low pH water or cases where a neutralizer tank cannot keep up.
- Tradeoff: more moving parts, more monitoring, more maintenance.
Option C: Caustic soda feed pump (advanced, higher risk)
- What it is: a pump injects sodium hydroxide.
- Best for: specialized cases with extremely low pH where other approaches fail.
- Warning: requires careful handling and professional oversight.
When you should add pre-filters
- Sediment filter: helps protect valves and media if you have sand, silt, or turbidity. Shop sediment filters.
- Iron, sulfur, or manganese issues: treat those with the right filter so your system performs consistently. Shop iron and sulfur filters.
Step 3: Install location and setup
- Install point-of-entry: treat all household water by installing where the well line enters the home.
- Confirm flow sizing: the system must match peak household demand (showers, laundry, dish, irrigation).
- Verify after install: re-test pH and (if previously elevated) copper and lead at the tap.
Step 4: Maintenance and monitoring
Neutralizer tank maintenance
- Replenish media: add calcite or blend as it dissolves. Check the tank periodically.
- Backwash (if your system backwashes): keep the bed clean and prevent channeling.
- Re-test pH: initially after installation, then periodically (for many homes, quarterly is plenty).
Chemical feed system maintenance
- Refill solution: keep the tank filled with correctly mixed solution.
- Calibrate pump: verify injection rate and pH output.
- Watch for overcorrection: too high pH can drive scale and deposits.
Troubleshooting
Blue-green stains on sinks or tubs
- Often indicates dissolved copper from corrosion. Test pH and copper, and consider lead testing too.
Metallic taste
- Common with low pH and corrosion. Confirm with pH plus metals testing, then treat at point-of-entry.
Pinhole leaks or recurring plumbing failures
- Strong sign of corrosive water conditions. Treat pH and consider replacing vulnerable sections of plumbing if needed.
FAQs
What pH is considered “acidic” for well water?
Any pH below 7.0 is acidic. In private well systems, corrosion concerns commonly increase below about 6.5.
Is acidic well water dangerous to drink?
Low pH itself is usually not the main health risk. The risk is corrosion, which can increase dissolved metals like copper or lead at the tap.
Do I need calcite or a calcite + corosex blend?
Rule of thumb: calcite around 6.0 or higher, blend below ~6.0 for stronger correction. Confirm by testing after install.
Will a neutralizer make my water harder?
Often, yes. Neutralizers can add calcium and magnesium, which can increase hardness and scaling in some homes.
When should I use soda ash injection instead of a neutralizer tank?
If your pH is very low (often below ~5.3), or if a neutralizer tank cannot keep up with your acidity and flow needs.
Should I test for lead and copper?
Yes if pH is low, you see staining, or you have older plumbing. Treating pH helps, but you should confirm metals at the tap.