How to Test for Chloramine in Tap Water (The Free vs Total Trick)

To test tap water for chloramine, use a test strip with two pads, one for free chlorine and one for total chlorine, dipped in one fresh glass of cold water. Subtract the free number from the total number: the gap is the chloramine. A free-chlorine strip on its own reads near zero on chloraminated water, so it can tell you there is no chlorine when your city is using chloramine.

Two numbers settle it, and the strip takes under a minute. Below is which test to buy, how to run it, how to read the gap, how your water report confirms it, and what a chloramine result changes for a fish tank, home dialysis and a carbon filter.

Why a free strip misses chloramine

Free-chlorine strips read near zero on chloraminated water. Free chlorine is the chlorine still loose in the water. Chloramine forms when the utility adds ammonia to that chlorine, so it is combined chlorine, and a free test is built to leave it out. ITS describes its free-chlorine strip as "designed to resist interference from monochloramines."

A total chlorine test reads both kinds at once. CDC gives the math: total chlorine minus free chlorine equals combined chlorine. On a city that uses chloramine, the combined chlorine is the chloramine it added.

EPA says chloramine keeps disinfecting longer in the pipes, and some cities switched to it to keep disinfection byproducts down. That is why a chloramine city can carry a total chlorine reading that a free strip barely registers. If you only want a chlorine number, see how to test for chlorine in tap water.

Which chloramine test should you buy?

Buy a strip that has a free pad and a total pad on the same strip. ITS WaterWorks 2 Free & Total reads 0, 0.1, 0.2, 0.5, 1, 2.5, 4 and 5 ppm, comes 30 strips in foil packets, and was $19.49 on the maker's site on October 14, 2026. Hach sells a free and total strip that reads 0 to 10 mg/L, 50 tests. LaMotte's Insta-Test Free and Total strip reads 0, 0.5, 1, 3, 5 and 10 ppm, 25 tests. With any of them you read two numbers and subtract.

A ppm is the same as a milligram per liter (mg/L). The fine steps at the low end matter more on chloramine water, because the free number you are reading is often near zero.

A DPD kit reads the same two numbers with liquid drops or tablets. The reagent turns the sample pink, and you match the color to the kit's chart. Hach's free chlorine method says to read the free result within 1 minute: chloramine slowly pushes a free reading up, and at 1 minute 3 mg/L of monochloramine adds less than 0.1 mg/L. The total test needs a 3-minute reaction, then a reading within 3 minutes.

Hach also says to test chlorine right away, because the sample cannot be preserved. That is why the number from your own sink beats a mailed sample. Our city water test kit is a lab panel for metals, minerals and other contaminants, and it does not report chlorine or chloramine.

How to test with a two-pad strip

These steps are printed on the ITS WaterWorks 2 Free & Total pack. Other brands time it differently, so follow the bottle you have.

1. Fill a clean glass with a fresh 250 mL (about 8 oz) sample of cold tap water, from a tap that is not behind a filter.
2. Take one strip from its foil packet and dip it for 10 seconds, moving it gently back and forth.
3. Pull it out and shake it once, briskly, to throw off the extra water.
4. Wait 15 seconds.
5. Match the free pad to the free row and the total pad to the total row on the chart, and write both numbers down.

Using two strips, or a free test and a total test from a kit? Draw one fresh sample and run both tests within a minute or two. Two different glasses, or one glass that sat on the counter, give you two numbers that do not belong together.

What your two test results mean

Total chlorine is never smaller than free chlorine, because it includes the free chlorine. The size of the gap points to which disinfectant your city uses.

Here is a real pair. A caller in Troy, Michigan read me the numbers from an in-home test last August: "0.20 free chlorine, 0.31 total chlorine. Combined chlorine was 0.12." Free is most of the total there, so that water was mostly free chlorine with a little combined chlorine, which points to a city using chlorine. On chloraminated water the free number sits low and the total carries most of it.

Up to 4 mg/L of either chlorine or chloramine is considered safe to drink, per CDC, and 4.0 mg/L is the federal limit for both. ITS marks 4.0 on its chart as the EPA maximum.

Have both chlorine test results?

Text Aidan your two test results

Send me your free number, your total number and your city. I'll tell you whether it reads as chlorine or chloramine, and whether you need a carbon filter for it.

Text Aidan443-277-2204 Call800-460-5810Aidan

8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.

Mistakes that hide chloramine on a test

• A free-only test. A free strip or a free-only meter reads near zero on chloraminated water and tells you nothing about chloramine.
• Two samples, or a slow free reading. Run both tests on one fresh glass. On a DPD kit, read free within 1 minute, or chloramine starts showing up as free chlorine.
• A filtered tap. A refrigerator dispenser, a pitcher or a whole house carbon filter can take chlorine and chloramine out, so the strip reads low or zero. Test at a tap ahead of the filter.
• The yearly chlorine switch. Some chloramine utilities switch to free chlorine for a short period each year as upkeep of the pipe network, and the water can smell more of chlorine then. Test during that window and you read mostly free chlorine. Palm Beach County, which does this, announces the dates by mail, email and on its website.
• Mailing the sample. Chlorine and chloramine cannot be preserved, so a lab reading of a mailed bottle is not your tap's number.

Is there chloramine in my tap water?

Your utility's yearly water quality report tells you. CDC says the report shows whether your water has a disinfectant, which kind, and its levels, and federal rules require the report to list every disinfectant held to the 4.0 mg/L limit. Here is how to read your water quality report.

A caller last August had ordered our 2.5 cubic foot carbon tank because "potentially there was chloramine issues." Then the caller read the report: "for the last 5 years says that they only use chlorine, and it's only 1.23 milligrams per liter." The report answered it before any strip did.

The report sums up a whole year across the system; your strip reads your own tap today. Use both. CDC notes that utilities switch disinfectants in both directions, so check this year's report, not an old one. For how the two disinfectants differ, see chloramine vs chlorine.

What a chloramine result means for your filter

A chloramine result decides which carbon to look for. Calgon, which makes Centaur, describes it as decomposing chloramines in drinking water faster than standard activated carbons. Centaur is what we use in our carbon tanks, and in my video on city water I put it this way: "Does carbon take out chloramines as well as chlorine? And yes, it does."

Every whole house carbon tank we sell uses Centaur catalytic carbon. I size it by the people in the house: 2 to 4 people, the 1.5 cubic foot tank ($1,495); 4 or more, the 2.5 cubic foot tank ($1,695). On city water I go non-backwashing: "You can use non-backwashing if it's city water." As I told the Troy caller, "The carbon tank's non-backwashing, doesn't need electric, doesn't need a drain or anything like that."

The one carbon product we sell that is not Centaur is the 20 inch Big Blue carbon kit ($259). Its cartridge is standard activated carbon, for chlorine taste and odor, and it is not the one to buy for chloramine. For the difference between the two carbons, see catalytic carbon vs activated carbon.

The same strip keeps working after the tank is in. A caller asked whether testing tells you when the carbon is used up, and I said: "Yep. You can check the chlorine level." Test the water after the tank now and then; when total chlorine starts coming through again, the carbon is getting spent.

Who needs chloramine taken out completely

Chloramine at the levels utilities are allowed to use is safe to drink, per CDC and EPA. Two groups need it gone completely.

• Fish, reptiles and amphibians. CDC says they absorb water straight into their bloodstream, so even low levels of chlorine or chloramine can make them sick. Pet stores sell water treatments that remove both; for chloramine water, buy one that says it handles chloramine.
• Home dialysis. CDC says dialysis water must have all chlorine and chloramine removed, and a home dialysis patient should check the machine's instructions or contact the manufacturer about treating the water. A strip tells you chloramine is there; it does not clear water for dialysis.

Palm Beach County, which uses chloramine most of the year, tells dialysis centers and fish tank owners to take precautions during its yearly switch to free chlorine.

Frequently asked questions