For a tankless heater, buy a pump kit: the Superior Pump 91660 descaler kit brings the pump, bucket, hoses and solution in one box. The Chromex flush kit does the same job with a bigger 5-gallon bucket and an NSF-certified solution. A tank heater is a different tool entirely — the Sediment Buster clears settled sediment through the drain valve.
Plumbing Picks is reader-supported. As an Amazon Associate, we earn from qualifying purchases at no extra cost to you.
“Water heater flush kit” covers two unrelated products: a circulating pump kit that pushes descaling solution through a tankless heat exchanger, and a tool that breaks up sediment sitting in the bottom of a tank. Buying the wrong one is the common mistake, so this page names both.
| Product | Best for | Heater type |
|---|---|---|
| Superior Pump 91660 Descaler Pump Kit | Best Overall | Tankless |
| Chromex Tankless Water Heater Flush Kit | Best 5-Gallon Kit | Tankless |
| The Original Sediment Buster Flushing Tool | Best for a Tank Heater | Tank |
Best OverallEditor’s Choice
Superior Pump 91660 Tankless Water Heater Descaler Pump Kit
1/6 HP oil-free submersible pump · 1920 GPH at 0 ft · 20 ft maximum head · 3.5 gallon pail with screw-on locking lid · two 6 ft, 3/4 in stainless steel hoses · non-toxic descaler solution · CSA and SSPMA certified · per Superior Pump’s product page
Check the Superior Pump 91660 kit on Amazon →
Superior Pump lists this as an all-in-one kit: the pump, a 3.5 gallon bucket with a screw-on spill-proof lid, two 6 foot stainless steel hoses, and the descaler solution. Everything lives in the bucket between jobs, which is the difference between a kit you actually use and one you assemble first.
The pump is the reason to pick this one. Superior lists an oil-free, water-cooled motor with solid copper windings and dual o-ring seals, 1920 gallons per hour at zero lift and up to 20 feet of head. Stainless hoses matter more than they look: they do not kink behind a wall-hung unit.
- Complete kit — pump, pail, two hoses and solution, per Superior Pump’s product page.
- Oil-free motor, so nothing can leave a film in a potable heat exchanger.
- Screw-on locking lid, so the bucket stores and carries without spilling.
- Only useful if your heater already has isolation valves fitted.
- A 3.5 gallon pail is on the small side for repeat circulation on a badly scaled unit.
- The pump is a general utility pump, so it is bulkier than a purpose-built circulator.
Verdict: Buy this if you want one box that does the whole job and will still be usable in ten years.
#ad
Best 5-Gallon Kit
Chromex Tankless Water Heater Flush Kit
Six-piece kit · 1/6 HP pump · 5 gallon bucket with lid · two 6 ft stainless steel hoses · citric-acid based, solvent-free descaling solution · solution certified to NSF/ANSI/CAN 60 · per the listing
Not linked: Chromex flush kit — on 10/3/2026 the Amazon listing was sold by a third-party seller, not by Amazon or the maker. We re-check listings every week.
Same shape of kit, bigger bucket. The listing describes six pieces: a 5 gallon bucket with a lid, a 1/6 HP pump, two stainless steel hoses and the descaling solution, and names compatibility with most tankless brands including Rinnai, Bosch, Noritz, Rheem, Takagi and Navien.
The solution is the part worth reading. The listing states it is citric-acid based and solvent free, safe for most metals, PVC, rubber and ABS, and certified to NSF/ANSI/CAN 60, the standard for drinking water treatment chemicals. That matters because whatever you circulate touches the same exchanger your shower water runs through afterwards. The listing puts a typical flush at 30 minutes or less.
- 5 gallon bucket gives more volume to circulate than a 3.5 gallon pail.
- Descaling solution certified to NSF/ANSI/CAN 60, per the listing.
- Stainless hoses and broad brand compatibility, per the listing.
- The listing does not publish a flow rate or head figure for the pump.
- A plain lid rather than a screw-on locking one.
- Liquid solution is bulkier to store than powder.
Verdict: Buy this if you want a bigger bucket and care about what the solution is made of.
#ad
Servicing water heaters for a living?
Best for a Tank Water Heater
The Original Sediment Buster Water Heater Flushing Tool
Connects to the tank drain valve · full-port design · clear viewing window · driven by a CO2 cartridge, air compressor or hand pump, sold separately · UL Solutions Verify ID V699054 · verified to withstand up to 80 psi at 100°F
Check the Sediment Buster on Amazon →
A tank heater does not scale the way a tankless one does. It collects hardness sediment on the floor of the tank, which is what makes a heater rumble and what blocks the drain valve when you finally try to flush it. A pump kit does nothing for that.
This tool attaches at the drain valve and uses pressure to break the sediment loose so it leaves with the water. Its claim is independently checked: the UL Solutions Verify entry V699054 records the verified marketing claim “withstands up to 80 psi at 100°F water temperature”, assessed with a 1.25x performance margin across eight samples at 2,000 cycles each, with zero samples showing cracking, leaking or damage afterwards. That is a rarer thing on a plumbing accessory than it sounds.
- Solves the problem a pump kit cannot: settled sediment in a tank.
- Pressure and temperature claim verified by UL Solutions under Verify ID V699054.
- Clear window lets you watch what is coming out, so you know when to stop.
- Needs a CO2 cartridge, compressor or hand pump, which the listing states is sold separately.
- No use at all on a tankless heater.
- On a heater that has never been flushed, a badly fouled drain valve may still have to be replaced.
Verdict: Buy this if your heater has a tank, rumbles, and has not been flushed in years.
#ad
What a Tankless Flush Kit Actually Contains
Four parts, and you need all four: a small submersible pump, a bucket, two hoses, and a descaling solution. The pump draws solution from the bucket, pushes it through the heater’s cold isolation valve, out through the hot one and back, so the same solution circulates until the scale is gone.
Do You Have the Isolation Valves?
Settle this before you buy anything. A tankless flush needs a pair of service valves with hose ports on the cold inlet and hot outlet, and plenty of units were installed without them. If yours has none, no kit on this page will connect, and fitting valves is a job on the heater itself.
Tankless or Tank: Two Different Jobs
A tankless heater drives water temperature up in seconds at a narrow exchanger, which is the condition that drops calcium onto the exchanger walls. You dissolve that with circulated acid. A tank heater’s problem is sediment settling above the burner, removed with water and agitation through the drain valve. If yours is rumbling, start with what a noisy water heater is telling you.
How Often, and Why Hardness Decides
Annually is the usual baseline, and hard water shortens it. The honest answer is that your manufacturer publishes an interval and often ties warranty coverage to documented maintenance, so read yours rather than a rule of thumb. If your water is hard enough to need two flushes a year, the better fix is upstream — see hard water signs and fixes. If a softener is the fix, our water softener picks show how to size one to your hardness.
How We Pick Water Heater Tools
Nobody pays to appear here. Picks come from field experience on real jobs — which tools hold up in actual homes and which ones cause callbacks — together with published manufacturer specifications read off the maker’s own documentation rather than guessed.
We pick for build quality and service life, because a tool that fails in two years has to be bought twice, and we name a small number of genuine winners instead of listing everything on the market. Full method: how we pick.
Why Trust Plumbing Picks
These picks come from a Journeyman Plumber — State of Georgia Licence #JP507711, verifiable through the Georgia Secretary of State’s license verification portal. Nobody pays to be featured and there are no sponsored placements. Some links here are Amazon affiliate links, so we may earn a commission at no extra cost to you, and that does not change which tool gets named. More on who writes this: about Plumbing Picks.
FAQ
What is in a water heater flush kit?
For a tankless heater: a small submersible pump, a bucket, two hoses and a descaling solution. The Superior Pump 91660 kit is listed with a 1/6 HP pump, a 3.5 gallon pail with a locking lid, two 6 foot stainless steel hoses and solution. A tank heater kit is a different thing — a tool that connects to the drain valve.
Can I use a flush kit on a tank water heater?
Not a tankless pump kit. A tank heater collects sediment on its floor rather than scale on an exchanger, so the job is draining and agitating through the drain valve, not circulating acid. The Sediment Buster is built for that, and its pressure claim is verified by UL Solutions under Verify ID V699054.
Do I need isolation valves to flush a tankless heater?
Yes. The pump has to connect to a service valve on the cold inlet and another on the hot outlet, both with hose ports. If your unit was installed without them, no flush kit will connect and valves have to be fitted to the heater first.
What solution should I circulate?
Something made for the job. The Chromex kit’s listing describes a citric-acid based, solvent-free solution certified to NSF/ANSI/CAN 60, the standard covering drinking water treatment chemicals. Whatever goes through the exchanger is upstream of every hot tap in the house, so the certification is worth reading before you substitute anything.
How long does a tankless flush take?
The Chromex listing puts most heaters at 30 minutes or less of circulation, plus setup and rinse. On a unit that has gone years without a flush, expect to change the solution and run it again rather than to force one pass to do the work.
Bottom Line
Buy the Superior Pump 91660 kit if you want one complete box and a pump worth keeping. Buy the Chromex kit if you want the same job with a certified solution and a bigger bucket. Buy the Sediment Buster if your heater has a tank, because no pump kit touches settled sediment. Then confirm your isolation valves before the box arrives.
Sources
- Superior Pump 91660 product page — kit contents, pump rating, head, certifications. Read September 2026.
- UL Solutions Verify ID V699054 — Sediment Buster, verified claim “withstands up to 80 psi at 100°F water temperature”, test routine and sample count. Read September 2026.
- Kit contents and solution certifications for the Chromex kit are read from its current Amazon listing, September 2026.