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Effective Dishwasher Drain Alternatives: Preventing Backflow

Dishwasher Drain Alternatives, The air gap is a requirement in plumbing codes to ensure that wastewater drains don’t back up into your home. The air gap is the pipe that goes from your sink to the wall or floor. It’s required because it increases the distance between your drain pipe and any potential sources of contamination, like food particles or small animals.

Back siphonage occurs when the dishwasher drains into the sink, which could lead to disgusting sewage entering your home. The air gap helps prevent this by forcing water to flow down and not back up. Dishwasher Drain Alternatives don’t have an air gap in your kitchen, there are several other ways to ensure that your dishwasher drains correctly.

The most common alternatives to replacing an old dishwasher air gap are using a high loop, standpipe, or using a different model of valve. You can also replace the existing air gap and install an air gap fitting specifically designed for use with dishwashers instead.

There are many ways to create an air gap — however, all of them need to be properly designed and installed to ensure their effectiveness.

Dishwasher Drain Alternatives looking for an alternative for your dishwasher, consider one of the following options:

Dishwasher Air Gap Alternatives

Dishwasher Drain Alternatives

Using a High Loop

In many cases, installing a high loop drain pipe in place of the traditional dishwasher air gap can be an effective and affordable alternative.

A high loop is basically a pipe loop that rises above the highest point in the drain system, including any trap or P-trap extending from it. This protects against backflow by preventing any trapped sewer gas from flowing back into the house through this location.

The high loop is installed in the same way as a standard dishwasher air gap. The only difference is that it rises above the highest point of the drain system rather than being placed at that spot.

To connect the high loop straight to the drain, you’ll need to draw out as much extra length from the existing drain line as possible. Then, arch it up under the sink and against its underside.

The high loop should also be installed in an area that is easily accessible for cleaning and inspection. It’s important to keep this pipe free of debris, especially if there are other pipes extending from it. This will ensure that any trapped sewage doesn’t have a chance to flow back into the house through a hole or crack in the system.


Standpipes can prevent backflow contamination without an air gap. The vertical standpipe lets water leave a structure. Standpipes are put above the P-trap in plumbing systems to quickly drain washing machines. They also make dishwasher draining easy.

But it’s not the greatest way to prevent backflow pollution. Standpipes aren’t required by code and may not be suited for all situations. They’re harder to install than air gaps or high loop drainpipes, so consult a plumber before picking them.

A standpipe costs more than a high loop since it requires numerous pieces of equipment, but it’s cheaper than installing multiple drain pipes throughout your home for your dishwasher.

Using a Check Valve

Check valves usually go in walls or floors. They let water to go one way but not the other. A check valve would be great for a pipe running vertically through your wall and connected to the outside of the building with a drainpipe that leaked into the basement (or vice versa).

However, check valves are usually not code-compliant and cannot replace air gaps in most situations. Small food particles can get through dishwasher drainage systems, but the check valve is not designed to manage them.

If debris or food gets in a check valve, it may not close properly, allowing backflow. Use the right air gap alternative to avoid seeing sewage when you open your dishwasher.

Check valves also require extra installation and maintenance. If you utilize a check valve (unrecommended), have a professional install it.

How to install a dishwasher drain line alternative

Dishwasher Drain Alternatives

Before installing a dishwasher drain line alternative, ensure that you comply with the plumbing code.

To connect the high loop to the drain, extend the drain line as far as possible. Arch it under the sink and against its underside.

Hold the loop with a strap or pin and grip the dishwasher drain line. To connect a T-branch tailpiece to your drain hose, use a Y-branch to connect two sections of tubing and clamp them. A dishwasher drain line is easy to install, but if you’ve never done it before, consult a plumber.


When you’re building a new home or remodeling an existing one, it’s sometimes necessary to install an air gap in the dishwasher drain line. An air gap is a device that prevents the backflow of sewer gases into your dishwasher.

But if you don’t have enough room for an air gap — or if your local code requires one — there are alternatives.

Replacing an old dishwasher air gap is often a matter of installing either a high loop, standpipe, or different valve. You can also choose to replace the existing air gap and install a new fitting instead.

Dishwasher Drain Alternatives are unsure of which option is best for you, consult with a professional plumber.