If you have a low-flow toilet (<1.6 gallons/flush), great, you're done. If you're not sure, check under the lid to see if it is listed. If you are looking to upgrade to one, there are many on the market that work well at below 1.3 gallons per flush, but they must be designed to do so (they usually work using higher pressures). If you upgrade, once you have it you'll be done with this guide.

If, however, you don't have one and don't want to invest in one, you can turn your own existing toilet into one. Go on to step 2 to find out how.

Fill a gallon milk jug with water and put it in the top basin. The idea is to have that jug cause less water to fill in the basin. If you need to weigh it down, you can add something heavy to the jug.

If you find that you don't have enough water with a one-gallon jug, try a smaller one. The key is to find the largest displacement volume to the point where the appliance is still working well.