The best water filters for TTHM

Utilities add chlorine or chloramine to kill germs, which EPA's science advisers have called the greatest remaining health risk for drinking water. But the disinfectants react with natural material in the water to form byproducts, and total trihalomethanes, or TTHM, are one of the two groups EPA limits. EPA limits them at 80 parts per billion and says long-term exposure above that may cause liver, kidney or nervous system problems and raise the risk of cancer. This guide ranks the filters certified to reduce them.

What a filter is certified to reduce is on its listing. Every TTHM claim here was read from WQA's and IAPMO's listings on October 22, 2026; the Multipure's, listed only by NSF, was last read on October 16. TapBuff has not tested these filters.

The picks at a glance

The picks at a glance

Filter	Pick	Certified for	Five years
Brondell Coral UC300 Under Sink Water Filtration System	Lowest five-year cost	Total trihalomethanes (TTHM), Lead, PFOA and 3 more	$900
Brita Elite Water Filter Faucet System (SAFF-100/FF-100)	Least up front	Total trihalomethanes (TTHM), Lead, Chlorine	$1,004
Aquasana Clean Water Machine (AQ-CWM2)	Lowest cost on the counter	Total trihalomethanes (TTHM), Lead, PFOA and 3 more	$1,061
Aquasana HealthShield (WH-HS)	For the whole house	Total trihalomethanes (TTHM), PFOA, PFOS and 2 more	$4,901+
Five-year cost for a household of 3 at the makers’ list prices, cartridges included; whole-house systems at 80 gallons each a day. A plus sign means a part due in those five years has no published price.

Is TTHM in your water over the limit?

EPA's limit isn't a single sample. Each sampling location's results are averaged over the past four quarters, and a utility violates the limit when that running average goes over 80 ppb. EPA says the byproducts form faster as water warms, which usually means higher TTHM in summer and in warmer climates.

Since 2016, 2,058 of the 36,209 utilities on TapBuff have had at least one TTHM violation, and 938 of them had one in 2023 or later. Together the 2,058 serve about 23 million people, by the populations they report to EPA. TapBuff's report for each utility shows its TTHM results where its state publishes them, and any violation; the lookup at the bottom of this page finds yours.

What counts as a TTHM claim

TTHM is a health claim under NSF/ANSI 53, separate from the chlorine claim under NSF/ANSI 42. A filter can carry it two ways:

• A TTHM claim. Some listings name it outright: "TTHM (as chloroform)" on WQA's.
• A VOC claim. NSF/ANSI 53's claim for volatile organic chemicals covers a list of them in one test, with chloroform standing in for the rest. IAPMO's certificates say that when a VOC claim is listed, the system can reduce every chemical on that list, and TTHM and chloroform are on it.

So a filter listed for chlorine taste and odor alone has not been certified for TTHM. That leaves out most of the filters people own:

• Pitchers. No pitcher in TapBuff's catalog carries a TTHM or VOC claim, Brita's and PUR's included.
• Shower filters. NSF/ANSI 177, the shower filter standard, covers free available chlorine only. A whole-house system with the claim is the certified way to treat shower water.
• Most whole-house filters. Aquasana's HealthShield is the one in the catalog with a VOC claim. The others carry none.
• Haloacetic acids. EPA limits HAA5, the other main group of byproducts, at 60 ppb the same way. No NSF or WQA listing TapBuff has found carries an HAA5 claim, so no filter here is certified for it.

How the picks are ranked

Every pick carries a TTHM or VOC claim under NSF/ANSI 53 on a certifier's listing, so they are ranked by what each costs over five years at the maker's list prices, with what else its listing covers beside it. The drinking-water figures are for a household of three using 3 gallons a day; the whole-house figure, for 80 gallons a person a day. Each is the system's list price plus every filter due in five years, with the first filters in the box. Installation is left out.

The picks

Brondell Coral UC300 Under Sink Water Filtration System

Lowest five-year costUnder-sink carbon

Best for a certified TTHM claim for the least over five years

Strengths

• VOCs, which cover TTHM, with lead, PFOA/PFOS, mercury and MTBE under NSF/ANSI 53, on WQA's listing
• Chlorine and chloramine under NSF/ANSI 42
• The lowest five-year cost of any filter here with a TTHM claim

Trade-offs

• $79.99 a set of three filters, replaced together at 600 gallons or 12 months
• Its own faucet goes through a separate 7/16-inch hole in the sink, so it takes some installing

Brita Elite Water Filter Faucet System (SAFF-100/FF-100)

Least up frontFaucet mount

Best for a TTHM claim on the faucet you have, for $32.49

Strengths

• VOCs, which cover TTHM, with lead and asbestos under NSF/ANSI 53, on WQA's listing
• $32.49 for the system, and $17.99 a filter
• Mounts on the end of your faucet, with nothing under the sink

Trade-offs

• Filter rated 100 gallons or four months: at 3 gallons a day, a new one about every 33 days
• No PFAS or chloramine claim

Aquasana Clean Water Machine (AQ-CWM2)

Lowest cost on the counterCountertop

Best for a TTHM claim with no plumbing, for the least over five years

Strengths

• VOCs, which cover TTHM, with lead, PFOA/PFOS, mercury and MTBE under NSF/ANSI 53, on WQA's listing
• Chlorine and chloramine under NSF/ANSI 42
• No plumbing: you fill it from the tap

Trade-offs

• Filters come only in pairs, each rated 300 gallons or about 6 months
• Not the older AQ-CWM, which takes a different filter

Aquasana HealthShield (WH-HS)

For the whole houseCarbon filter

Best for a TTHM claim at every tap, the shower included

Strengths

• VOCs, which cover TTHM, with PFOA, PFOS, PFHxS, PFNA and PFHpA under NSF/ANSI 53, on WQA's listing
• The one whole-house system TapBuff tracks with the claim
• Rated 5.7 gallons a minute and 165,000 gallons

Trade-offs

• $4,198, and Aquasana publishes no price for the replacement tank, so its five-year figure leaves out two of them
• The whole system is replaced when the 165,000 gallons run out: about every 23 months for a household of three
• WQA's listing says aluminum has to be reduced before the water reaches it

The other eleven with a TTHM claim

These carry the claim too, at a higher five-year cost than a pick that does the same job, or with no price to total.

Under the sink. The A.O. Smith AO-US-200, $980; the Aquasana Claryum 2-Stage, $990; the Claryum Direct Connect, $1,078, which feeds your own faucet; the Multipure Aquaversa, $1,215; and the Claryum 3-Stage Max Flow, $1,278.

On the counter. The AquaTru Classic, $1,344, reverse osmosis with fluoride, arsenic and nitrate claims; the Brita Hub, $1,545; and the Ninja HydraSense, $2,050, with a Total PFAS claim.

Reverse osmosis under the sink. The Brondell Capella RC250, $1,950, and the Aquasana SmartFlow, $2,917.

With no five-year total. PUR publishes no prices for its PLUS faucet filter, which WQA lists for TTHM by name.

The under-sink, faucet, countertop and whole-house guides rank each kind against everything else of its type. If your utility uses chloramine, the chloramine guide ranks the filters with that claim.