If you have ever used a modern toilet, you may have noticed that many of them have 2 buttons on top of the tank used to flush the toilet. There is usually a smaller button and a larger button right next to each other. This dual flush mechanism allows you to choose between a lighter, shorter flush or a heavier, longer flush depending on your needs.
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The Purpose of Dual Flush Toilets
Dual flush toilets were designed specifically to help conserve water. By giving users the option between a lighter and heavier flush, people can choose to use less water for lighter jobs. The lighter flush option uses significantly less water than a standard, single flush toilet.
For example, the lighter flush may use as little as 0.8 gallons per flush while a standard flush uses 1.6 gallons per flush. If you only need to get rid of liquid waste, the lighter 0.8 gallon flush is sufficient and uses half as much water. For more solid waste, the heavier 1.6 gallon flush can be used to ensure everything is washed down the drain.
Water Savings from Dual Flush
Being able to choose between a lighter and heavier flush can lead to considerable water savings over time, especially in bathrooms that get frequent use. Here are some statistics on dual flush toilet water use:
- An average family of 4 can save up to 13,000 gallons of water per year with a dual flush toilet.
- Dual flush toilets use 32% less water on average than standard 1.6 gallon flush toilets
- If a full 1.6 gallon flush is not needed, the 0.8 gallon flush saves 50% of the water used in one flush
As you can see, the water savings from dual flush toilets really add up, especially for families. The EPA estimates that if just 1 in every 4 US households installed dual flush toilets, it would save nearly 520 billion gallons of water over the next decade. That’s equivalent to the annual household water needs of more than 4.9 million US homes!
How Dual Flush Toilet Mechanisms Work
Dual flush toilets operate through the use of a flush valve mechanism inside the tank. There are a few different designs, but they all work to release different amounts of water from the tank depending on which button is pushed.
Button Mechanism
One of the most common dual flush designs has two buttons on top of the toilet tank that are mechanically connected to the flush valve inside the tank. Pushing the smaller button pulls the chain connected to the valve and releases only a portion of the water in the tank into the bowl.
Pushing the larger button activates the entire flush valve to open and releases all of the water from the tank into the bowl. The tank then refills to prepare for the next flush.
Float Mechanism
Another dual flush design uses a split float system inside the tank. There is a large main float that controls the overall tank water level and a smaller secondary float connected to the flush valve.
When the small button is pushed, it lifts only the secondary smaller float which opens the valve halfway to release some water. Pushing the large button lifts the entire mechanism and opens the valve fully to empty the tank.
Release Mechanism
Some dual flush toilets have a release button inside the tank instead of dual buttons on top. Pushing the button halfway down activates a restrictor that limits how far the flush valve will open. Pushing all the way down allows the valve to open completely.
In all cases, the dual buttons or mechanisms allow for two preset flush volumes – one lighter and one heavier. The internal tank mechanisms are what differentiate how much water flows into the bowl.
Types of Dual Flush Toilet Options
If you are looking to purchase a dual flush toilet, there are a few considerations to keep in mind to select the right model:
- Bowl Shape – Dual flush toilets come in both round and elongated bowl shapes to match your bathroom space.
- Toilet Height – Standard or comfort height options are available depending on your needs.
- Flushing Power – Check the MaP (Maximum Performance) score for flushing power – higher is better.
- Water Usage – Lighter flush usage can range from 0.8 – 1.1 gallons while the heavier flush is usually 1.6 gallons.
- Design Styles – From modern to classic, dual flush toilets come in many styles to match your existing bathroom decor.
The flushing power and water usage will depend on the specific dual flush toilet model. Be sure to read reviews and product details carefully before purchasing.
Top Dual Flush Toilet Brands
Some of the leading toilet manufacturers making high-performing dual flush toilet models include:
- Toto
- Kohler
- American Standard
- WoodBridge
- Swiss Madison
Within each brand’s line, you will find many style, bowl, height, and flushing power options to choose from. Prices range from around $300 – $600 for most dual flush toilet models.
Pros and Cons of Dual Flush Toilets
Here is an overview of some of the key pros and cons to consider with dual flush toilets:
Pros
- Saves significant water compared to standard 1.6 gallon flush toilets
- Lighter flush works well for liquid waste removal
- Heavier flush provides power for solid waste removal
- Easy to operate with two buttons to choose from
- More environmentally friendly
Cons
- Higher upfront cost than standard single flush toilets
- Some dual flush mechanisms may be less reliable and more prone to breakdowns
- Low-flow lighter flushes may require extra flushing for solid wastes
- Some models may have weaker flush strength compared to powerful single flush toilets
The main drawback is the higher initial purchase cost. However, the water savings over time usually far outweigh the added upfront investment.
How to Use Dual Flush Toilets
It is important to learn how to use dual flush toilets properly to get the most efficiency and benefits. Here are some tips:
- For liquid waste only, press the smaller flush button for the shorter 0.8 gallon flush
- For solid waste removal, use the larger 1.6 gallon heavy flush
- Do not hold down flush buttons – a quick press activates the flush
- Wait for the tank to fully refill between flushes
- Adjust flush volume based on waste – use lighter flush whenever possible
With a little practice, using a dual flush toilet will become second nature. Just remember to utilize the lighter flush option whenever you can to maximize water savings.
Troubleshooting Dual Flush Issues
On occasion, you may run into problems with your dual flush toilet mechanism. Here are some steps to try troubleshooting common issues:
- Check for clogs – a clogged toilet can cause poor flushing and the need for multiple flushes.
- Clean debris from the flush valve – built-up debris can prevent proper valve closure.
- Check chain/lever connections – disconnected parts can prevent flushes.
- Make sure float moves freely – a stuck float prevents proper operation.
- Check fill valve – faulty fill valves will not allow enough water into the tank.
For continued problems, consulting a plumber may be needed for repairs or replacements of dual flush parts. The good news is that the dual flush mechanisms have continued to improve over time.
Conclusion
Dual flush toilets provide homeowners with a proven way to cut down on unnecessary water usage and waste. The two button options allow you to tailor the water volume to the need. Lighter flushes efficiently remove liquid wastes, while the heavier full flushes provide solid waste removal power when needed.
While more expensive upfront than standard single flush toilets, dual flush models pay for themselves over time through considerable water savings. On average, you can expect to save 13,000 gallons per year with a dual flush toilet!
When shopping, be sure to look for a dual flush toilet from a leading brand with a good MaP score and an easy to use flush mechanism. With proper use and maintenance, a dual flush toilet will provide many years of reliable, high-efficiency performance.