How to Convert Any Toilet Into a Low-Flow Toilet

A stark bathroom interior with a simple toilet
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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 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.



  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.
  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.
  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.
  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.

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.