What’s a Dual-Flush Toilet?
The names “Single-Flush” and “Dual-Flush” can fool you. They don’t refer to how often you have to push the handle or button to get the toilet to function. Instead, the terms indicate the water volume used after you press.
Manufacturers worked with the EPA and other government bodies to set a standard for amounts of water used.
A single-flush toilet has only one method of operation. You push the button and the toilet flushes waste. It does that by using maximum 1.6 GPF (gallons per flush) as required by the Energy Policy Act of 1992. For those interested here’s the section in question:
A dual-flush toilet, by contrast, gives you 2 flushing options. You can save water by using the “low water volume” mode (0.8 GPF) for liquid waste. Sometimes even small amounts of semi-solid matter can be cleanly flushed with just a “half volume” flow. Or you can use the “full volume” mode (1.6 GPF) to eliminate fecal matter, large amounts of toilet paper, and any other time you need more water to accomplish complete removal.
Any toilets sold in the U.S. today will satisfy at minimum the 1.6 GPF standard. They’re all technically “low volume” toilets, sometimes known as High Efficiency Toilets (HET). As such, they use no more than 1.6 GPF. In 2006 that standard was supplemented by the government-regulated “WaterSense” program, which requires using no more than 1.28 GPF in order to earn that label. Read here why you should look for a WaterSense toilet.
Why Buy a Dual-Flush Toilet?
Years ago, and with many old units still in use in older houses, a flush would consume about five gallons of water from the toilet’s tank. If you have a large family living at home that can add up to a lot of water in a month’s time. That’s both a big percentage of your total utility bill and, especially in dryer areas of the country, a potential environmental problem.
That’s what encouraged manufacturers to create the more advanced dual-flush water-conserving technology. The technology is primarily intended for water conservation – both as an environmental value and to save you money on your water bill. The end result can mean savings of a fair percentage off your total bill, especially if you still have one or more old and inefficient models using a big tankful.
Cost is a factor, naturally. Dual-flush toilets are usually more expensive. But considering that a toilet may last 20, 30, or even 50 years or more (with proper maintenance), that probably shouldn’t be the most important criterium. That higher cost can be offset – sometimes a lot – by considering the savings a dual-flush model can deliver.
For example, an average family of five can use up to 34,000 gallons of water less per year when replacing an old 5-GPF toilet with a Watersense-labeled toilet. You can calculate your water savings here. The figures are very approximate, of course.
But consider how many times a day your old 5-GPF toilet gets flushed in your house. Multiply by 5 gallons per flush times 365 days per year. Then do the same exercise but replace 5 with 1.28 gallons per flush. The difference is what you will roughly save with a Watersense-labeled single-flush toilet. With a dual-flush toilet with its 2 flushing options you will save even more water.
To turn that into dollar savings look at how much your utility company charges per gallon and do a little arithmetic. Over the course of a few years, the water savings can definitely offset some of the purchase cost.
Single-flush toilets are the type you will invariably find in older houses. Really old or particularly inefficient toilets may use much more than the 1.6 GPF required by law today.
There are now converter kits available that can reduce the amount of water used per flush. A dual-flush toilet converter like the FlushSaver Conversion Kit effectively turns your traditional single-flush toilet into something resembling a modern high-efficiency dual-flush type.
The best option, if you’re remodeling, is to go ahead and buy a dual-flush toilet. They are more costly, but it may be a relatively small percentage of your overall budget, and they can last for 50 years or more. Some use as little as 0.8 gallons of water per flush.
In consequence, a home with five family members and an older toilet can save as much as 6,800 gallons of water per person per year. That water savings can definitely offset some of the purchase cost.
Whether it’s a WaterSense, HET, single or dual-flush or some other variation you buy, you’d be hard-pressed these days to find a toilet of any type that couldn’t handle a high amount of waste in a single flush. They all do the job.
Of course, that claim needs a caveat. If your house is older, or your utility or well offers only very low pressure all bets might be off. They might be adequate, they might not. No toilet can function properly if it lacks enough water pressure. Only a measurement could tell you for sure. Most will be fine but if you have any doubts a low-cost pressure gauge – or a visit from a professional – can set your mind at ease.