Best Water Saving Toilet When Space Is Tight

The best water saving toilet here is the Gerber Maxwell Select, a two-piece dual-flush that runs 1.28 gpf on a full flush and 1.0 gpf on the reduced setting. If you'd rather cut water use without buying a fixture, the Fluidmaster 400H fill valve is the cheaper path. Note first: this set mixes complete toilets with tank repair kits, and the two solve very different problems. The price tiers map cleanly onto that split, so read the tier before you read the specs.

Best water saving toilet picks at a glance

How I narrowed a crowded field to five

I set the criteria first, then weighted them, because a search for the best water saving toilet returns two things pretending to be one. Whole fixtures and the parts that go inside a tank. Both save water. They cost and install nothing alike.

My weighting, in order:

1. Stated flush volume. The lower and the more clearly listed, the better. This decided the top of the ranking.
2. What you get in the box. A complete toilet outranks a single valve for a shopper starting from nothing.
3. Fit clearance. A retrofit part is only water-saving if it actually fits your tank.
4. Published warranty. Two picks state one. Three do not.

What that weighting cut: anything with no flush figure at all, and any part that only claims to "restore performance" without touching water volume. The Fluidmaster 400AKRP10 survived on its stated 1.6 to 3.5 gpf compatibility, even though that range runs high, because it rebuilds the whole mechanism in one box. Here's the honest caveat up front. Amazon's search returned kits alongside toilets, so "water saving" is only partly satisfied by the listings. You judge the final gallons at your own tank.

Replace the toilet or retrofit the tank?

This is the fork that decides everything. Buy a new fixture, or fix the one bolted to your floor.

A full replacement resets the flush volume to whatever the new bowl is rated for. The Gerber Maxwell Select ships with its 1.28/1.0 gpf mechanism and a soft-close seat already included. You get a known number. You also get 81.9 lb of porcelain to wrestle into place and a wax ring to reseat.

A retrofit changes the tank's guts and leaves the bowl alone. The Danco HydroRight converts a standard toilet to dual flush, and the maker claims a drop-in install in 5 to 10 minutes with no tank removal. Cheaper, faster, lower risk. But your bowl's flush volume is still whatever it was, and the kit only saves on the reduced setting.

• Starting from a bare bathroom or a cracked bowl? Replace.
• Toilet works but wastes water or leaks? Retrofit.
• Renting? Retrofit, and keep the old parts.

1. Gerber Maxwell Select — Best overall

A complete two-piece dual-flush that gives you a known 1.28/1.0 gpf number and a soft-close seat in one box.

Best for: a full replacement in a standard bathroom Skip it if: you only want to fix your current toilet

The Maxwell Select is the only pick here that arrives as a finished, ready-to-flush fixture with a stated dual-flush split. Gerber lists 1.28 gpf for a full flush and 1.0 gpf for the reduced one, driven by what the listing calls a split-flush mechanism. That is a genuine water-saving spec, not a retrofit promise. The elongated soft-close seat is included, which the other complete toilet in this set also offers but the repair kits obviously cannot.

Dimensions run 31 x 28.5 x 17.5 in and it weighs 81.9 lb, so this is a two-person carry and a real install job. Gerber points to a canister flush valve and a glazed trapway to keep waste moving. Those are the maker's claims about clog resistance, not measured results.

It carries the highest price position of the five and sells slower than the parts do. That is the trade-off for buying the whole thing instead of a valve. What you get for it is certainty about the gallons per flush from day one.

Pros:

• Stated 1.28 / 1.0 gpf dual flush volume
• Complete fixture, nothing else to source
• Elongated soft-close seat included
• Canister flush valve claimed for strong clearing

Cons:

• Highest price position in this set
• 81.9 lb makes install a two-person job
• No published warranty in the listing
• Only one seller stocks it

2. Fluidmaster 400H Universal Toilet Fill Valve — Best budget pick

The cheapest fix here, a quiet universal fill valve with adjustment dials and the longest warranty in the set.

Best for: a quiet, adjustable fill valve swap Skip it if: you need to add a dual-flush lever

The 400H is the cheapest of the five and the fastest-moving part in its category by a wide margin. At 0.6 lb it is a single valve, not a system. Fluidmaster claims it is the quietest, most powerful fill valve available. Treat that as marketing, not a measurement. What matters for water is the pair of adjustment dials for tank and bowl water level, which let you dial in a lower fill and stop the tank from overfilling.

It carries a 7 year manufacturer warranty, the longest here. The EZ-Twist height adjusts from 9 in. to 14 in., so it fits most tanks without hunting for a size. Two sellers list it.

The limit is scope. A fill valve controls how much water enters the tank, not how the flush itself works, so it saves at the margins rather than halving your usage. If your tank runs on and wastes water between flushes, this is the surgical fix. If you want two flush volumes, look at the Danco instead.

Pros:

• Cheapest pick in the set
• 7 year manufacturer warranty, longest here
• Tank and bowl level dials for tuning
• Height adjusts 9 in. to 14 in.

Cons:

• Controls fill only, not flush volume
• Quietness claim is unverified
• No dual-flush option
• Multicolor listing, parts vary

3. Fluidmaster 400AKRP10 Universal Toilet Repair Kit — Best minimal setup

One box rebuilds fill, flush and flapper, restoring a tired tank without the guesswork of buying parts separately.

Best for: a full internal rebuild in one box Skip it if: your flush volume is already low

The 400AKRP10 is the middle price tier and the second-cheapest pick. It bundles the fill valve, a 2-inch flush valve and a PerforMAX flapper into one kit, so a tank that leaks, runs or fills slowly gets a clean sweep rather than a patch. Fluidmaster says it installs in 10 minutes or less. It weighs 8 oz and carries a 5 Year warranty.

The universal design fits most 2-inch flush valve toilets, and the maker states it works on toilets from 1.6 to 3.5 gpf or larger. That range is the honest catch. It restores an existing toilet rather than lowering its rated flush, so if your bowl is an old 3.5 gpf model, this rebuilds it at 3.5 gpf. The water saving comes from stopping leaks and overfill, and from the adjustable flapper Fluidmaster calls water-saving.

Against the Danco, it trades dual-flush capability for a complete rebuild. Against the 400H, it fixes the flush side too, not just the fill.

Pros:

• Complete rebuild, fill, flush and flapper
• Second-cheapest pick here
• 5 Year warranty stated
• Claimed 10-minute install

Cons:

• Rebuilds existing volume, does not lower it
• Fits toilets as high as 3.5 gpf
• No dual-flush lever
• Single seller listed

4. Danco HydroRight Universal Dual Flush Kit — Most versatile

The one part here that adds two flush volumes to a toilet you already own, no new fixture required.

Best for: adding dual flush without a new toilet Skip it if: your tank lacks the clearance

The HydroRight is the mid price tier and the most interesting retrofit in the set, because it changes what a standard single-flush toilet actually does. Danco says it converts a standard toilet to dual flush, cutting the water used per flush. It weighs 1.54 lb and installs drop-in without tools in 5 to 10 minutes, with no tank removal. The adjustable height runs 11 to 13.8 inches.

The split handle is the clever bit. The short center lever is a quick flush for liquids and paper, and Danco notes that setting is needed four out of five times. That is where the saving lives. Two sellers list it, more than most picks here.

Fit is the whole story. It works with standard 2 in. flush valves and needs a 10-inch minimum clearance from the top of the flush valve opening to the inside of the lid. Measure that before you buy. Against the Gerber, it costs far less but leaves your bowl's base volume untouched, so it saves only when you choose the quick flush.

Pros:

• Adds true dual flush to an existing toilet
• Tool-free drop-in install claimed
• Quick-flush lever for the common case
• Two sellers stock it

Cons:

• Needs 10-inch tank clearance to fit
• Saves only on the reduced setting
• No stated warranty in the listing
• Requires standard 2 in. flush valve

5. DeerValley Compact One-Piece Toilet — Best upgrade

A skirted one-piece built for tight bathrooms, with the lowest reduced-flush figure of any complete toilet here.

Best for: a compact one-piece for a small bathroom Skip it if: you have room for a standard footprint

The DeerValley is the premium tier and the pick for a cramped bathroom. Its footprint is 27.8 x 24.6 x 13 in, tighter than the Gerber's, and it uses a 12-inch rough-in. DeerValley lists a dual-flush system with a full flush at 1.28 gpf and a half flush the listing renders as 0.8 gpf. That reduced figure is the lowest half-flush claim among the complete toilets here.

It is a one-piece design, so there is no tank-to-bowl seam to leak or clean around, and the fully skirted trapway gives a smooth face for wiping down. A soft-close removable seat is included. It weighs 88 lb, the heaviest pick, and a one-piece is awkward to maneuver in a small room.

Against the Gerber, it wins on footprint and on that lower half-flush number, but it sits at a similar premium price and, like the Gerber, publishes no warranty. Choose it when floor space, not budget, is the constraint. In a standard bathroom the two-piece Maxwell is the easier install.

Pros:

• Compact 27.8 in. depth for small rooms
• Claimed 1.28 / 0.8 gpf dual flush
• One-piece, no tank seam
• Soft-close seat included

Cons:

• Heaviest pick at 88 lb
• Premium price position
• No published warranty
• Only one seller lists it

How much water does dual flush actually save?

Dual flush works by giving you two buttons: a full flush for solids and a reduced one for liquids and paper. The saving is real but conditional. It only shows up when the reduced setting gets used.

The math is straightforward from the listed figures:

• The Gerber's full flush is 1.28 gpf, its reduced 1.0 gpf. That's a 0.28 gallon gap.
• The DeerValley claims 1.28 gpf full and 0.8 gpf reduced, a wider 0.48 gallon gap.
• Danco says the quick flush is needed four out of five times, which is where a retrofit earns its keep.

So a household that presses the light button most of the time saves more than the raw full-flush number suggests. A household that always hits full flush saves nothing over a single-flush toilet of the same volume. Behavior decides it. The number on the box is a ceiling, not a promise.

Will these parts fit the toilet you own?

Two of these picks are toilets and drop onto a standard flange. The three tank parts each have a fit rule, and a mismatch means it does not save water because it does not seat.

• Danco HydroRight needs standard 2 in. flush valves and a 10-inch minimum clearance from the flush valve opening to the lid underside. Its height adjusts 11 to 13.8 inches.
• Fluidmaster 400AKRP10 fits most 2-inch flush valve toilets and adjusts from 9 to 14 inches, rated for 1.6 to 3.5 gpf tanks.
• Fluidmaster 400H is a fill valve only, EZ-Twist adjustable from 9 in. to 14 in., a universal fit for most tanks.

Before ordering any of the three, lift your tank lid and measure two things: the flush valve opening diameter and the clear height inside the tank. A 2-inch valve is the common size. If yours reads bigger or smaller, these kits may not seat correctly, and a poorly seated valve leaks rather than saves.

When a different pick wins

The Gerber leads, but the right buy flips on your situation.

• If your bathroom is genuinely small, the DeerValley wins on its 27.8 in. depth and its claimed 0.8 gpf half flush.
• If you own a working toilet that just leaks or runs, the Fluidmaster 400AKRP10 rebuilds it for a fraction of a new fixture.
• If you want dual flush but not a new toilet, the Danco HydroRight adds the two-button lever in minutes.
• If only the tank refill is the problem, the 400H fill valve is the cheapest, most surgical fix.

The verdict

The best water saving toilet for most bathrooms is the Gerber Maxwell Select. It is the pick that hands you a known 1.28/1.0 gpf number the moment it's installed, with a soft-close seat already in the box. You are not guessing at gallons or hunting for parts. If you're outfitting a bathroom from scratch or replacing a cracked bowl, this is the default.

If the DeerValley Compact is the runner-up, its exact advantage is dimensional and numerical: a 27.8 in. depth that fits where the Gerber won't, and a claimed 0.8 gpf half flush that is the lowest reduced figure among the complete toilets here. That is the cutoff. Below a certain floor space, or when you want the deepest possible water cut on the light flush, the DeerValley takes it. Above that, in a standard room, the two-piece Gerber is the simpler, cheaper-to-install choice.

The three tank parts are not lesser toilets. They are a different decision entirely, for a toilet you already have and don't want to replace.

FAQ

Is the best water saving toilet worth the higher price?

The best water saving toilet earns its price when you're replacing a fixture anyway or starting from a bare bathroom. The Gerber's 1.28/1.0 gpf split cuts water on every reduced flush for years. If your existing toilet works and only leaks, a repair kit gets you most of the saving for far less, so the fixture is worth it mainly on new installs.

How much water does a dual-flush toilet actually save?

How much water a dual-flush toilet saves depends on which button you press. The Gerber runs 1.28 gpf full and 1.0 gpf reduced, a 0.28 gallon gap. The DeerValley claims 1.28 down to 0.8 gpf. Danco notes the light flush is needed four out of five times. Use the reduced setting often and the saving is real; always hit full and you save nothing.

Will the Danco HydroRight fit my toilet tank?

Whether the Danco HydroRight fits comes down to two measurements. It needs a standard 2 in. flush valve and a 10-inch minimum clearance from the flush valve opening to the inside of the tank lid. Its height adjusts 11 to 13.8 inches. Lift your lid and measure both before ordering. A tank shorter than 10 inches inside won't take it.

Gerber Maxwell or DeerValley Compact: which should I pick?

Between the Gerber Maxwell and DeerValley Compact, footprint decides it. The DeerValley is 27.8 in. deep with a claimed 0.8 gpf half flush, built for small bathrooms. The Gerber is a standard two-piece at 1.28/1.0 gpf, easier to carry and install in pieces. Choose the DeerValley for tight space, the Gerber for a normal-sized bathroom.

What water-saving mistake do most buyers make?

The most common water-saving mistake is buying a retrofit kit expecting it to lower a high-volume bowl. A fill valve or repair kit restores an existing toilet, so a 3.5 gpf tank stays 3.5 gpf. Only a new low-flow fixture, like the Gerber's 1.28 gpf, resets the base volume. Match the fix to the actual problem first.

Start by lifting your tank lid and checking two things: whether the toilet leaks or runs, and what your bowl's flush volume is. That answers the whole question. A working bowl that wastes water at the fill takes the 400H valve. A tired mechanism takes the 400AKRP10 rebuild. A single-flush toilet you'd like to make smarter takes the Danco converter. And a bathroom starting from nothing takes the Gerber Maxwell Select, the one pick that hands you a real 1.28 gpf number without any measuring at all.

Last updated: September 7, 2026. Product availability re-checked.

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