Dual Flush Toilets: How They Work

Toilets may seem fairly simple, but their designs have continued to evolve to use water more efficiently while still providing the flushing power homeowners need. One option you may have come across is the dual flush toilet.

Unlike a traditional toilet that uses the same amount of water with every flush, a dual flush toilet gives you two flushing options. One uses less water for liquid waste, while the other provides a fuller flush for solid waste.

But how do dual flush toilets work, and are they worth considering for your bathroom? Here’s what you should know.

What Is a Dual Flush Toilet?

A dual flush toilet is designed with two flush settings instead of one. Most models have two buttons on top of the tank, although some use a two-position handle.

The smaller flush is intended for liquid waste and uses less water. The larger flush releases more water to handle solid waste.

The main benefit is simple: You don’t have to use a full tank’s worth of water every time you flush.

How Do Dual Flush Toilets Work?

Although exact designs vary by manufacturer, dual flush toilets typically use a flush valve that can release different amounts of water depending on which button or setting you choose.

When you select the reduced flush, the valve allows a smaller amount of water to move from the tank into the bowl. This is usually enough to clear liquid waste.

When you select the full flush, the valve releases a larger volume of water to provide more flushing power for solid waste.

This differs from many traditional gravity toilets, which generally use the same flush volume each time. If you’re interested in how other flushing systems compare, read our guide to gravity vs. pressure-assisted toilets.

How Do Dual Flush Toilets Save Water?

The advantage of having two flush options is that the toilet can use less water when a full flush isn’t necessary.

That can add up over time, particularly in a home where the toilet is used frequently. Older toilets can also use considerably more water than today’s efficient models, so upgrading an outdated toilet can provide additional opportunities to reduce household water use.

When shopping for a new toilet, you can also look for models with the WaterSense label. These toilets are designed to meet water-efficiency and performance requirements, and WaterSense labeled dual flush toilets include a reduced-flush option for liquid waste.

Pros of Dual Flush Toilets

Dual flush toilets can offer several advantages for homeowners:

• Reduced water use: The lower-volume flush lets you use less water when a full flush isn’t needed.
• More control: You can choose the appropriate flush based on the type of waste.
• Modern efficiency: Many newer dual flush models are designed with water conservation in mind.
• Potential long-term savings: Using less water can help reduce household water consumption over time.

For homeowners replacing an older or inefficient toilet, a dual flush model can be one option to consider when comparing new fixtures.

Cons of Dual Flush Toilets

Dual flush toilets aren’t necessarily the right choice for every bathroom. There are a few potential downsides to consider:

• Higher upfront costs: Some dual flush models can cost more than basic single flush toilets.
• More cleaning may be needed: Because reduced-flush models use less water, some bowls may require more frequent cleaning.
• Different components: Dual flush mechanisms can differ from the traditional flapper systems many homeowners are familiar with.
• Users have to choose the correct flush: The water-saving benefits depend in part on people actually using the reduced flush when appropriate.

Quality and performance also vary by model, so water efficiency shouldn’t be the only factor you consider when choosing a new toilet.

Can You Convert a Regular Toilet to Dual Flush?

Dual flush conversion kits are available for some traditional toilets. These kits replace or modify parts of the existing flushing mechanism so you can choose between two flush volumes.

However, not every toilet is a good candidate for conversion. Compatibility, the condition of the toilet and the existing flushing system can all affect how well the conversion works.

If your toilet is already old, inefficient or frequently needs repairs, replacing it with a newer model may make more sense than retrofitting the existing fixture.

If your toilet is having problems such as continuously running water, you may also want to determine whether the issue can be repaired before deciding to replace it. Our guide on why a toilet keeps running covers several common causes.

Is a Dual Flush Toilet Right for Your Home?

A dual flush toilet can be a good choice if water efficiency is one of your priorities and you like having more control over how much water each flush uses.

Before buying one, consider the toilet’s flush performance, water usage, price and maintenance requirements. You should also make sure the model works well with your home’s existing plumbing.

If you’re replacing an old toilet or need help deciding which type will work best in your bathroom, Shamrock Plumbing can help. Learn more about our toilet installation and repair services or contact us to discuss your plumbing needs.