The Lowdown on Low-Flow Toilets

By Debbie Wolfe | Advertiser Disclosure

Flushing your toilet is the main source of water use in the average home and makes up about 31 percent of overall household water consumption. In fact, a full-flush toilet uses about six gallons of water in a single flush. You can conserve the amount of water used by your home’s toilet by checking for leaks, using a composting toilet, or upgrading to a low-flow toilet.

What is a low-flow toilet?

A low-flow toilet is a flush toilet that uses about 1.6 gallons of water per flush. Not only does this conserve more water than a traditional toilet, it saves you money on your monthly water bills. In the early 1990s, the U.S. government mandated that all new toilets on the market be low-flow. However, in many older homes, toilets are still full-flush.

Low-flow toilets vs. full-flush toilets

On the surface, both toilets look nearly identical. The biggest difference between a low-flow toilet and a full-flush, or regular, toilet is the amount of water used per flush.

  • Full-flush toilets—These traditional toilets feature a simple valve and flapper mechanism. They rely on the force of gravity from gallons of water to flush out liquid and solid waste. 
  • Low-flow toilets—These toilets use gravity or pressure to clear out waste.

Types of low-flow toilets

There are two types of low-flow toilets: gravity or pressure-assisted.

  1. Gravity—Similar to how a full-flush toilet works, this type of low-flow toilet clears waste when the flush valve is engaged and releases water from the tank. However, it uses significantly less water than a regular toilet.
  2. Pressure-assisted—A pressure-assisted toilet uses a compressed pocket of air to create water pressure that releases into the bowl and clears out waste with each flush.

How do low-flow toilets work?

A gravity-fed and pressure-assisted low-flow toilet work in different ways

Gravity-fed

Although these water-saving toilets work similarly to full-flush toilets, their internal flow models are slightly different. 

  • The drain outlet is more centered in the bowl versus being at the back in full-flush toilets.
  • The flush valve has a wider diameter which allows the faster release of water with more force.
  • The toilet bowl is designed so that more water rests toward the front.
  • It uses about 1.6 gallons per flush.

Pressure-assisted

This toilet works by using a burst of air to move waste from the bowl. There’s no water inside the tank; instead, there’s a pressure tank that works similar to a water balloon. When water fills the tank, it’s held there under pressure and is released when the flush valve opens (the compressed air pushes water with force into the bowl, moving the waste out).

  • Increased force aids in cleaning the bowl and pushing water further through sewer pipes.
  • This type of low-flow toilet is noisier than gravity-fed ones.
  • This low-flow toilet uses the least amount of water per flush.

Issues with low-flow toilets

Although low-flow toilets use sufficiently less water, they aren’t issue-free.

  • Pressure-assisted toilets are loud—they make a distinctive “whooshing” sound every time you flush. 
  • The toilets may not force waste far enough down the drain, which can lead to clogs and other plumbing issues.
  • If your home is older or has low water pressure, it may cause the toilet not to work sufficiently.

How much do low-flow toilets cost?

The average cost of low-flow toilets range from $125–$300, but they can cost upward of $1,000 or more. Installation costs for low-flow toilets average between $200–$350. 

How to choose a low-flow toilet

With so many types of low-flow toilet styles and prices, it can be hard to narrow down the best low-flow toilet for your home. Here are some factors that influence how well a new toilet performs:

  • Waste removal—How well a toilet removes waste from the bowl without a lot of water is paramount. Ensure that the water pressure in your home will work with a gravity-fed system. If not, it may be worth looking into a pressure-assisted system.
  • Design—Round and taller bowls tend to flush more efficiently. 
  • Efficiency—Stick to models labeled as high-efficiency toilets. They will give you the most water and financial savings.
  • WaterSense label—Look for the “WaterSense” label from the Environmental Protection Agency (EPA). These toilets are tested by independent laboratories to make sure they use no more than 1.28 gallons per flush and clear waste effectively.

Best low-flow toilets

Lower your water bill and reduce your carbon imprint with a low-flush toilet. Here are our top three picks:

Summary

TOTO CST454CUFG#01 Drake II

Summary

This toilet features a hole-free rim design with dual-nozzles that create a centrifugal washing action, which assists in rinsing the bowl more efficiently.

Niagara 77001WHCO1 Stealth

Summary

The Niagra low-flow toilet features an ultra-efficient, pressure-assisted toilet that’s affordable and stylish.

American Standard 2887.216.020 H2Option Siphonic Dual Flush

Summary

American Standard is a popular and reliable toilet brand. This dual-flush toilet gives you the option of using either a partial flush or a full flush.

TOTO CST454CUFG#01 Drake II

The TOTO CST454CUFG#01 Drake II is a beautifully designed high-profile toilet. It features an exceptionally smooth glaze that prevents particles from adhering to the ceramic and a “Tornado Flush” capability that reduces the frequency of toilet cleaning. Both elements minimize the use of water, harsh chemicals, and time required for cleaning.

Pros:

  • An elongated bowl design for added comfort
  • Has a universal height, making it easy to sit on or stand up
  • Two-piece toilet that’s easy to install
  • EPA WaterSense labeled
  • 1.0 GPF

Cons:

  • Some customers have reported clogging issues
  • The soft close seat is sold separately

Niagara 77001WHCO1 Stealth 

The Niagara Stealth toilet is one of the most affordable low-flow toilets available. It features a comfortable, elongated bowl and uses pressure-assisted flush to clear waste with only 0.8 gallons per flush. 

Pros:

  • Helps conserve water at home
  • Extremely quiet 
  • ADA-compliant
  • EPA WaterSense labeled
  • 0.8 GPF

Cons:

  • Some customers have reported clogging issues
  • It doesn’t come with a toilet seat or wax ring

American Standard 2887.216.020 H2Option Siphonic Dual Flush 

American Standard offers high-quality and affordable toilets. This low-flow toilet gives you the option of using either a partial flush or a full flush with the press of an actuator button on top of the toilet tank. It features an elongated toilet bowl for added comfort and power wash rims that keep bacteria, mildew, and mold at bay.

Pros:

  • Elongated bowl design for comfort
  • Quick installation process
  • Comes with an easy-to-use push button actuator
  • Elegant design
  • EPA WaterSense labeled
  • 1.0 GPF for partial flush and 1.6 GPF for full flush

Cons:

  • It doesn’t come with a seat

Are low-flow toilets worth it?

Low-flush toilets conserve water and limit a home’s impact on the environment. While low-flow toilets can be  more expensive to install and maintain, they can save you money over time.

Frequently asked questions

Do low-flow toilets smell?

If there isn’t enough water to push waste through the sewer system, the sewage can cause a blockage and cause odors. However, properly functioning low-flush toilets will not smell.

Are low-flow toilets OK to use with septic systems?

Yes, low-flow toilets are used by homeowners that don’t have a residential sewage system and are ideal for cutting down on the amount of water that enters the septic systems.

Are low-flow toilets good for the environment?

Yes, low-flush toilets help reduce how much water you use when flushing a toilet, thus conserving more water and saving you money in the long run.

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