Save up to 35% on select items with code FALL26
Save up to 35% on select items with code FALL26
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1.0 GPF Toilets

TOTO's 1G range uses 1.0 gallons per flush, well below the 1.28 WaterSense limit and around 37% less water than a 1.6 gallon toilet.

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Water savings

Against a 1.6 gallon toilet, a family of four saves roughly 5,000 gallons a year. Against a 1.28, around 2,500.

Many water authorities offer rebates for high-efficiency toilets, and 1.0 GPF models qualify comfortably where 1.28 sometimes sits at the threshold.

Does 1.0 GPF flush properly?

On these models, yes. TOTO engineered the bowl and trapway around the lower volume rather than simply restricting the water, and the 1G models use the same TORNADO FLUSH systems as the rest of the range.

One thing to check

Very low flush volumes leave less margin in older plumbing. If your drain run is long or has a shallow slope, it is worth a word with us or your plumber before ordering — this applies to any 1.0 gallon toilet, not just TOTO's.

Frequently Asked Questions about 1.0 GPF Toilets

What does 1G mean on a TOTO?

It marks a model that uses 1.0 gallons per flush rather than the standard 1.28.

Will a 1.0 GPF toilet clog more?

Not on a modern TOTO. The bowl is designed around the volume rather than restricted.

How much water does 1.0 GPF save?

Roughly 5,000 gallons a year for a family of four, compared with a 1.6 gallon toilet.

Is 1.0 GPF legal everywhere?

Yes. It is below every state limit, including the 1.28 requirements in California and Texas.