Best Toilet Repair Kits of 2026

The Fluidmaster 400CRP14 is the repair kit we recommend first because it fixes the two parts that cause almost every running toilet, pairing the time-tested 400A anti-siphon fill valve with a quality 2-inch flapper and a fresh tank-to-bowl gasket, all in a universal kit that fits the vast majority of standard tanks.

The 400CRP14 bundles Fluidmaster's flagship 400A fill valve, which adjusts from roughly 9 to 14 inches in height to match nearly any tank, with a durable rubber 2-inch flapper and the gasket and bolts to reseat a leaking tank-to-bowl connection. The 400A uses an anti-siphon design that meets plumbing code, refills the tank reliably, and adjusts water level with a simple clip on the float, so you can fine-tune flush volume. Because the flapper is a standard 2-inch size, it drops onto the overflow pegs of the overwhelming majority of older and current two-piece toilets without modification.

Owners consistently report that this kit cures a running or constantly refilling toilet in well under an hour, that the 400A is the fill valve they have trusted for decades, and that parts are stocked at every hardware store if anything ever needs replacing. The two limits are scope: it does not include a new flush valve body, so a cracked or warped flush valve seat needs a complete rebuild kit instead, and it is not aimed at brand-specific canister tanks from Kohler or Toto. For the most common running-toilet problems on a standard tank, it is the standout pick, and it pairs naturally with the bowls in our guide to the best flushing toilets.

The Korky 528 is the pick when you want to rebuild the entire tank in one go, replacing the fill valve, the flush valve and the flapper together so a tired toilet with multiple worn parts works like new, all from a brand that supplies original equipment to major toilet makers.

The 528 is a full tank rebuild in a box. Beyond the QuietFILL Platinum fill valve, which Korky tunes for a quiet, fast refill, it includes a complete 2-inch flush valve assembly with a fresh seat and a flapper, plus the tank-to-bowl gaskets and bolts you disturb when you swap the flush valve. Because the flush valve is included, this kit fixes the problems a fill-and-flapper kit cannot, namely a cracked, warped or pitted flush valve seat that lets water weep past even a brand-new flapper. Korky is an original-equipment supplier to several major brands, so the parts are engineered to the same standards as factory components.

Owners value being able to address every worn part at once rather than chasing one leak after another, and they praise the quiet, quick refill of the Platinum valve and the leak-free seal of the new flush valve. The tradeoffs are time and effort: replacing the flush valve means removing the tank from the bowl, so this is a longer, more involved job than a flapper swap, and it is overkill if only the flapper or fill valve has failed. For a comprehensive overhaul on an aging tank, it is the standout pick, and it suits the same owner reading our guide to the best toilet fill valves of 2026.

The Fluidmaster PRO45B is the pick for high-traffic and commercial-grade reliability, pairing the heavy-duty PRO45 fill valve with a durable flapper in a kit built to handle frequent flushing in busy households, rentals and light commercial settings without premature wear.

The PRO45B is built around Fluidmaster's professional-grade PRO45 fill valve, a sturdier version of the 400A aimed at installers and high-use environments. It uses the same reliable anti-siphon, height-adjustable design but with heavier internals tuned to survive frequent cycling, hard water and the wear that thins out a standard valve in a busy bathroom. The kit adds a durable 2-inch flapper and the shank washer needed to reseat the valve, so it covers the same running-toilet fixes as the overall winner with parts chosen for longevity rather than rock-bottom cost.

Owners in rentals, large families and small commercial settings value the extra durability, reporting that the PRO45 holds up where cheaper valves start hissing or sticking sooner, and that the refill stays quiet and consistent under heavy use. The tradeoffs are a slightly higher cost than the basic kit and, like the overall winner, no included flush valve, so a damaged flush valve seat still needs a full rebuild. For a toilet that gets flushed constantly and needs to keep working, it is the smart heavy-duty pick, and it suits the same buyer comparing our guide to the best toilet flappers of 2026.

The Korky 818 is the pick for anyone bothered by a noisy refill, pairing the QuietFILL Platinum fill valve, engineered to fill the tank quickly and almost silently, with a universal flapper, so a toilet near a bedroom or in a quiet home stops announcing every flush.

The 818 is built around Korky's QuietFILL Platinum valve, which Korky designed specifically to reduce the hissing and rushing noise a standard fill valve makes as the tank refills. It still uses an adjustable, anti-siphon design that meets plumbing code and fine-tunes water level, but it routes the refill water to run quieter and finish faster, which is the main reason buyers choose it over a basic 400A kit. The included universal flapper handles the other half of the running-toilet equation, so the kit cures both a leaking flapper and a noisy or slow fill in one job.

Owners with toilets near bedrooms, nurseries or shared walls value the noticeably quieter refill, and many report the tank fills faster than the valve it replaced. The tradeoffs are that, like the overall winner, it does not include a flush valve body, so a damaged flush valve seat needs a complete kit, and it is aimed at standard tanks rather than brand-specific canister designs. For a buyer whose main complaint is refill noise, it is the standout pick, and it pairs well with the quiet bowls in our roundup of the best flushing toilets.

The Fluidmaster 400AKRP10 is the best bare-essentials kit, pairing the same reliable 400A fill valve as the overall winner with a universal flapper but skipping the extra gasket, so buyers who only need the two parts that cause a running toilet pay the lowest sensible price.

The 400AKRP10 strips the Fluidmaster formula to the two parts that fail most often. It includes the trusted 400A fill valve and a 2-inch flapper, the exact combination that cures the overwhelming majority of running toilets, but leaves out the tank-to-bowl gasket and bolts found in the complete 400CRP14, which keeps the cost down for buyers whose tank seal is fine. The 400A remains height adjustable and anti-siphon, so it fits and performs identically to the version in the winning kit.

Owners value getting the same dependable fill valve and flapper for less when their tank-to-bowl connection is not leaking, and they report the install is the simplest in the lineup since there is no tank to remove. The tradeoff is scope: if your toilet also weeps at the tank-to-bowl seam, you will want the complete 400CRP14 with its gasket instead, and like the other fill-and-flapper kits it does not address a damaged flush valve. For a buyer who has diagnosed a running toilet and just needs the valve and flapper, it is the smart, low-cost buy, and it suits the same shopper reading our guide to the best toilet flappers of 2026.

The Korky 2004A is the pick when the flush valve seat itself is damaged, bundling a complete 2-inch flush valve with a fresh seat, a flapper and the QuietFILL fill valve, so a toilet that leaks past a new flapper finally seals for good.

The 2004A targets the failure that stumps most do-it-yourselfers: a toilet that keeps running even after a brand-new flapper, because the flush valve seat the flapper presses against is pitted, warped or cracked. Rather than just another flapper, the kit supplies a full 2-inch flush valve with a clean, smooth seat, plus the QuietFILL fill valve and flapper, so you rebuild the entire sealing surface. Because it is a standard 2-inch flush valve, it fits the most common tank design, though buyers with a larger 3-inch flush valve need that size instead.

Owners who had chased a phantom leak through multiple flappers value finally curing it by replacing the seat, and they appreciate getting the quiet fill valve in the same box. The tradeoffs are the longer install, since fitting a flush valve means removing the tank, and the need to confirm your flush valve diameter, because a 3-inch tank will not accept a 2-inch valve. For a toilet whose flush valve seat is the real culprit, it is the standout pick, and it pairs with the diagnostics in our guide to the best toilet fill valves of 2026.

The Toto THU338 is the pick for Toto owners, supplying the genuine fill valve assembly engineered for Toto tanks, so the replacement matches the original fit and water level exactly rather than forcing a universal part into a tank designed around specific components.

Toto tanks are engineered around their own fill and flush components, and while universal parts often work, a genuine Toto fill valve removes the guesswork on fit and restores the exact factory water level and flush volume. The THU338 supplies that genuine assembly for many popular Toto two-piece tanks, so the valve seats correctly, clears the tank lid, and works with Toto's flush valve and flapper as designed. For owners of a Toto Drake, Ultramax or similar model, matching the original part is the surest way to keep the flush performing as it did new.

Owners value the confidence of an exact-fit genuine part and report the refill returns to factory quiet and the water level lands where it should without fiddling. The tradeoffs are that it is Toto specific, so it is useless on other brands, and it addresses the fill valve rather than a worn flapper, which Toto sells separately. Always confirm the part matches your exact Toto model, since the lineup uses several tank designs. For a Toto owner, it is the right buy, and it suits the same shopper reading our brand guide within the best flushing toilets roundup.

The Kohler GP1138930 is the pick for Kohler canister-flush toilets, supplying the genuine canister seal and flush components that fit Kohler's distinctive 360-degree flush design, which universal flapper kits do not match, so a running Kohler finally seals.

Many modern Kohler toilets use a canister flush valve rather than a flapper, a tower that lifts straight up for a fast 360-degree flush and seals with a single large rubber gasket at its base. When a canister Kohler runs, the culprit is almost always that base seal, and a universal flapper kit simply will not fit. The GP1138930 supplies the genuine Kohler canister seal and related parts so the canister seats and seals as designed, restoring the strong flush and stopping the leak that no flapper could fix on these tanks.

Owners of canister Kohlers value that the genuine seal drops in and cures a running tank that universal parts could not touch, and many note the canister design is simpler to service than they expected once they have the correct part. The tradeoffs are that it is Kohler canister specific, so it is the wrong choice for a standard flapper toilet or any other brand, and you must confirm your Kohler actually uses a canister rather than a flapper. For a canister Kohler owner, it is the only correct buy, and it suits the same reader comparing models in our guide to the best flushing toilets.