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1. What are high efficiency toilets?

High-efficiency toilets (HETs) are specially designed to use less than 1.3 gallons per flush (gpf) while still providing superior flushing performance. That’s a 20% savings over the previous standard of 1.6 gpf, also known as ultra low flush toilets (ULFTs.)

2. What about performance?

Todays high-efficiency toilets perform as well as or better than conventional, less efficient models. Information about flushing performance of specific toilet models can be found on the Maximum Performance (MaP) testing website.

3. How do I choose an HET?

To help consumers identify high performance, water efficient toilets that can reduce water use in the home and help preserve the nations water resources, the EPA sponsors the WaterSense program. The WaterSense label is used on toilets that are certified by independent laboratory testing to meet rigorous criteria for both performance and efficiency. Only high efficiency toilets that complete the third party certification process earn the WaterSense label.

4. Are there different kinds of HETs?

There are three main types of HETs, which operate slightly differently and yield slightly different water savings:

Dual-Flush: Dual-flush toilets save water by offering two different flush volumes, one for solids and one for liquids, so you save water by only using what you need. Most dual-flush toilets use 1.6 gpf for a full flush and 0.8 gpf for a reduced flush. Studies show these toilets average about 1.3 gpf.

Pressure-Assist: Pressure-assist toilets compress a pocket of air inside a sealed chamber as water fills. When flushed, the pressurized air forces the water rapidly into the bowl, creating a powerful, fast flush that has a “whoosh” sound. The flush can be slightly louder than standard toilets.

Single-Flush: A few manufacturers do offer HETs that utilize a single-flush—what many would describe as a “standard-style” toilet. These toilets use no more than 1.28 gpf.

5. How can I determine how much water my toilet uses?

See our information sheet on How to Check Your Toilet’s Flush Volume.

6. How do I replace my old toilet?

For step by step instructions, visit the do-it-yourself website's section on toilet replacement.

7. How do I dispose of my old toilet?

The Marin Resource Recovery Center at 565 Jacoby Street in San Rafael will dispose of your old toilet for a minimal fee. Contact the Center directly at 415-485-5647 for more information.

8. More questions?

If you have questions regarding high efficiency toilets, please email the Water Conservation Department or call 415-945-1520.