GPM is gallons per minute, a flow rate, whereas plumbing systems at the fixture level are usually “gallons per flush/cycle” (gpf or gpc). The old tried and true standards ran at 6 gallons per flush. Modern toilets have decreased to 2.4 gpm and is now 1.28 gallons gpf.
The current federal standard for toilets is 1.6 gallons per flush. This federal standard passed in 1992, so if your toilet was installed before 1992, it most likely uses 3.5 GPF to 7 GPF.
Flush Facts
Design improvements have allowed toilets to use 1.28 gallons per flush or less while still providing equal or superior performance. This is 20 percent less water than the current federal standard of 1.6 gallons per flush.
A toilet will normally use about 2-3 gallons per minute (gpm), a shower from 1.5 to 3.0 gpm, a bathroom or kitchen faucet from 2-3 gpm, a dishwasher from 2-4 gpm, and a washing machine from 3-5 gpm.
Low-flow toilets are specifically designed to use the least amount of water possible to flush waste and can use as little as 0.8 to 1.28 gallons for each flush. Homeowners can save as much as 4,000 gallons of water per year when they use one or more low-flow toilets.
1.6 Gallons Per Flush ( gpf ) is a little over one and a half gallons ( 6 quarts ) of water and 1.28 gpf is a little more than 1 and a quarter gallons of water (5 quarts ) per flush. So if you're looking to save water, which I highly recommend, the 1.28 gpf is the way to go.
Toilet performance is graded with a MaP score, which represents the number of grams of waste that are eliminated from the bowl in a single flush. A toilet with a score of 1,000g – 600g is considered to have Great Flushing Performance and will remove up to 35 oz. of waste in a single flush.
A standard showerhead flows at a rate of 2.5 gallons per minute . This means that a ten-minute shower only uses 25 gallons of water. A full bath can use up to 50 gallons of water .
Toilet Water Saving Tips
Toilets made from the early 1980s to 1992 typically used 3.5 gallons per flush (13.2 liters) or more. Toilets made prior to 1980 typically used 5.0 to 7.0 or high gallons per flush (18.9 lpf to 26.5 lpf).
On average, approximately 70 percent of that water is used indoors, with the bathroom being the largest consumer (a toilet alone can use 27 percent!).
The Environmental Protection Agency (EPA) estimates that 13,000 gallons of water can be saved annually in homes that use dual flush toilets.
The average shower water usage is calculated by multiplying that average flow rate of 2.1 gallons per minute by the average shower length of 8.2 minutes. So, 17.2 gallons is, on average, how much water is used. In a 10-minute shower, you'll go through 21 gallons.
The current national standards for toilets took effect in 1994 and set a maximum water use of 1.6 gallons per flush (gpf). In 2010, DOE officially waived federal preemption of the national toilet standard.
The U.S. Environmental Protection Agency (EPA) estimates that about 26 percent, or 7 million, of the 27 million flushometer-valve toilets currently installed in commercial and institutional facilities nationwide flush at volumes higher than the 1.6 gallons per flush (gpf) federal standard—some as much as 3.0 to 7.0 gpf ...
Flush volume refers to how much water is released when a toilet is flushed. Since January 1994 all. toilets sold in the U.S. must use 1.6 gallons per flush (gpf) or less. More recently, high-efficiency toilets. (HETs) with a flush volume of 1.28 gpf or less have been available.
The water flow rate is the measurement of how fast treated water will come out of your faucets throughout your home. It's measured in gallons per minute (GPM). The average household has a water flow rate of 6 to 12 GPM.
1.6 GPF: Which is More Efficient? GPF stands for “Gallons per Flush.” Naturally, a 1.28 GPF toilet uses less water than a 1.6 GPF toilet. However, efficiency isn't just about the numbers. A 1.28 GPF toilet is designed for low water usage, which can be beneficial for conservation.
The Toilet's Age
A general rule of thumb is to replace a toilet around every 25 years, though your mileage may vary.
Those standards went into effect in 1994. Since then, new toilets sold must not exceed 1.6 gallons per flush (gpf); faucets are capped at 2.5 gallons per minute (gpm), and showerheads may not spray more than 2.5 gpm.
The total running time of this kind of shower can last less than two minutes – using an initial thirty seconds or so to get wet, followed by shutting off the water, using soap and shampoo and lathering, then rinsing for a minute or less.
Compare that with standard flow rates across the U.S. For the standard home, a typical GPM looks something like this: Kitchen faucet: 2-3 GPM. Shower: 1.5-3 GPM. Dishwasher: 2-4 GPM.
Those bottles hold 5 gallons of water. That's how much water some older toilets use with every flush. Toilets manufactured before the 1980s use up to 6 gallons per flush (GPF). Your toilet may not be quite that old—but even toilets manufactured in the early 1990s use up to 3.5 GPF.