How to Reduce the Water Usage of Any Toilet

Adjustable toilet flapper installed to control water flow for toilet flush

The Spruce / Kevin Norris

Project Overview
  • Working Time: 15 mins - 1 hr
  • Total Time: 15 mins - 1 hr
  • Skill Level: Intermediate

Standard toilets can use as much as seven gallons of water per flush. Low-flow toilets use a mere 1.6 gallons. If you crave the water savings of a low-flow toilet but aren't ready to shell out money for a new model, you're in luck. With a few simple modifications, you can turn your water-guzzling toilet into a water-sipping, low-flow-style commode.

The beauty of many of these toilet water-saving devices is that most are easy to install, no matter how much of a plumbing novice you may be. Start with the adjustable flapper and tank bag, which are ridiculously easy to install.


Note that low-flow toilet design is not just tied to the amount of water used by the toilet. Manufacturers have redesigned toilets to be low-flow with adjustments to minimize water usage without hurting performance. While these tricks can reduce the amount of water used, it may reduce the toilet's effectiveness.

What You'll Need

Equipment / Tools

  • Plumbing tools (as needed)


  • Adjustable flapper
  • Toilet tank bag
  • Fill cycle or fill valve diverter
  • A leak detection tablet


Materials and tools to convert toilet into a low-flow toilet

The Spruce / Kevin Norris

  1. Install an Adjustable Flapper

    Several manufacturers make toilet flappers that can be adjusted to control how much water flows into the toilet when it is flushed. Check which model of toilet you have, and purchase the right flapper. Then, install the adjustable flapper in your toilet. Experiment until you find the right setting for your needs, giving enough of a flush to wash away the contents, without wasting water.

    Water savings: Up to three gallons per flush.

    Orange adjustable flapper installed to control water flow when flushed

    The Spruce / Kevin Norris

  2. Install a Tank Bag

    Purchase a tank bag. It serves the same purpose as putting a brick in your tank, without the risk of having the brick dissolve. Just fill the bag with water and hang it in your toilet tank. It'll displace some of the water, thereby reducing the amount of water needed to refill the tank after each flush.

    Water savings: An amount equal to the size of the bag.

    Blue toilet bag filled with water and inserted into toilet tank

    The Spruce / Kevin Norris

  3. Install a Fill Cycle Diverter

    The toilet tank and bowl may fill at the same time, but they don't fill at the same rate, (the bowl fills faster). Since the fill valve doesn't shut off until the tank is full, this means that water continues to be fed to the bowl. So, where does this extra water go? Straight down the drain! Install a fill cycle diverter to eliminate this waste. It's a small piece that connects to the fill line and overflow tube. It's designed to divert water back to the tank, once the bowl is full.

    Water savings: A half-gallon or more per fill.

    Orange fill cycle diverter connected to fill line and overflow tube in toilet tank

    The Spruce / Kevin Norris

  4. Check for Leaks

    Retrofitting your toilet with water-saving devices is great, but it doesn't mean much if you've got a leaky toilet. Pick up a free leak detection tablet from a home improvement store, and make sure your toilet is performing the way it should be. If you find a leak, figure out how to fix it.

    Water savings: Varies, depending on the severity of the leak.

    Leak detection tablet placed in toilet tank to check for leaks

    The Spruce / Kevin Norris

Additional Tips

  • All toilets are different, so you may need to experiment to figure out which techniques, or combination of techniques, work best for you.
  • Do not use a brick to displace water. Over time, it can dissolve and clog the drain.
  • Proceed with caution if you decide to use a plastic bottle in place of a tank bag. It could interfere with your toilet's mechanisms and result in an overflow. It's better to spend a few bucks on a bag that's designed to serve this purpose.
  • Many utility companies provide these water-saving devices to customers for free. Check with your local utility company before you go out and buy anything.
  • All of these devices can be purchased online if you aren't able to find them locally or don't want to deal with the hassle of tracking them down.
  • Whenever you have new toilet hardware to install, it's a good idea to do it on a day that you'll be home, so you can ensure everything is working properly (or catch the problem quickly, if something fails to work as it should). Don't make changes to your toilets right before you head out of town.
  • Remember, there are tons of ways to reduce your water usage and reduce your water heating bill.