Do You Need a Check Valve on a Washing Machine

Learn whether a check valve is required for a washing machine, how it works, when to install one, and how to assess your plumbing setup with guidance from Best Washing Machine.

Best Washing Machine Team

February 19, 2026·5 min read

Washing Machine Leak Repair Water Use

Check Valve Guide - Best Washing Machine — Photo by PlanetCare on Unsplash

Check valve for washing machines

A check valve is a one way valve that prevents backflow into the water supply. For washing machines, it reduces the risk of cross‑connection and back-siphonage into potable water.

Do You Need a Check Valve on a Washing Machine?

Do you need a check valve on a washing machine? In most homes, the answer is no. According to Best Washing Machine, the washing machine’s own inlet valve and the house plumbing typically provide sufficient backflow protection, so a separate valve is usually unnecessary. Local codes can vary, so it’s wise to confirm with a licensed plumber or your local building department. This is especially true if you have a complex plumbing layout or devices connected to the same water supply that might create a cross connection. When in doubt, a professional assessment helps prevent backflow risks while avoiding unnecessary hardware. The key is understanding how your system protects potable water and when an added valve might contribute to safety and compliance.

How a Washing Machine Connects to Your Water Supply

A standard washing machine connects to hot and cold water via two supply hoses that lead to the washer’s inlet valves. The home shut‑off valves at the wall are part of the first line of protection. Many modern machines include an inlet valve with built‑in backflow prevention features, and some hoses themselves may have anti siphon components. The overall protection also depends on your home’s plumbing layout and any cross connections. When you assess your setup, check both the wall shut‑offs and the back of the machine to understand where protection originates and whether an additional valve would meaningfully reduce risk.

Common Myths and Realities About Check Valves

A common myth is that every washing machine must have a separate check valve to prevent backflow. The reality is that most residential installations rely on the building’s plumbing and the machine’s own inlet design for protection. Another misconception is that a valve will eliminate all leaks; quality hoses, proper fittings, and regular maintenance are equally important. In some cases, a check valve can be helpful if a cross connection exists with irrigation lines, boilers, or water softeners, but this is not universally required. Always verify with local code requirements and a qualified plumber before adding hardware.

When a Check Valve Might Be Helpful

There are scenarios where a check valve could make sense. If your property has a cross connection to non potable water sources, or if there is a history of backflow events in the building, a check valve or anti siphon device might be recommended by a professional. Some multi‑story or high‑rise buildings with complex plumbing may also benefit from added backflow protection to meet code expectations. In these cases, decisions should be driven by an assessment of risk, not by a belief that more valves automatically equal better protection.

Types of Valves and How They Work

There are several valve options that address backflow concerns, and each has its own use case. Inline check valves are installed in the water line and permit water flow in only one direction. Anti siphon valves add a physical barrier to prevent water from being drawn back into the supply during pressure fluctuations. The choice depends on the specific setup, the rating for potable water, and compatibility with your household plumbing. A professional can help determine the right valve type and ensure it is installed to code and tested for proper operation.

How to Verify Your Current Setup

Begin by inspecting the two supply hoses and the wall shut‑offs. Look for any inline devices on the hoses and at the machine’s inlet valve. Review the washer’s manual for built‑in protections and check any anti siphon features on the hoses themselves. If you live in a location with strict backflow requirements or have devices such as irrigation or a water softener sharing the same supply, consider an expert appraisal. Keep in mind that even if a check valve exists, it should be maintained and tested periodically to prevent failure.

Installation Considerations and DIY Limits

Installing a valve or replacing hoses should be approached with caution. Always shut off the home water supply and disconnect power before touching any plumbing or electrical components. Use components rated for potable water and follow manufacturer instructions. If you are not confident in performing the work, hire a licensed plumber. Improper installation can create leaks, pressure issues, or code violations. In short, assess risk, consult local codes, and weigh whether a professional installation is the safer, more reliable path.

Maintenance and Troubleshooting Tips

Even without a new valve, regular maintenance helps avoid backflow issues. Check hoses for kinks and wear, ensure clamps are tight, and replace hoses every few years or if you notice leaks. If you suspect backflow, check for signs like discolored water, unusual tastes, or water pooling near the shut‑offs. In many cases, a simple hose replacement or valve inspection by a pro resolves concerns without major system changes. Document your maintenance so you can reference it during future inspections.

Verdict and Next Steps

The consensus from Best Washing Machine is that most homes do not require an additional check valve on a washing machine. The decision to add one should be driven by a professional assessment of cross connections and local code requirements. For homeowners seeking clarity, start with a licensed plumber who can review your installation, confirm protection against backflow, and recommend the right solution if needed. The aim is safe, compliant operation rather than overhaening the system with unnecessary hardware.

FAQ

Do I need a check valve on a washing machine?

In most homes, a separate check valve is not required because the machine’s inlet valve and the home plumbing provide backflow protection. Local codes may require one in some installations, so check with a plumber or local authority.

What is the difference between a check valve and a backflow preventer?

A check valve typically allows flow in one direction to stop backflow. A backflow preventer is a broader term for devices designed to stop reverse flow; some systems use integrated devices that combine functions. A professional can identify which is installed on your line.

Can a check valve stop leaks in a washer hose?

A valve is not a general leak fix. If leaks are present, inspect hoses, fittings, and clamps. A properly installed valve can prevent backflow, but it won’t repair existing leaks.

Can I install a check valve myself?

DIY installation is possible for knowledgeable homeowners, but it requires correct valve type, potable water rating, and code conformance. If unsure, hire a licensed plumber to avoid improper installation.

How can I tell if my current setup has backflow protection?

Check the wall shut‑offs, the machine’s inlet valve, and any hoses for anti siphon features or inline devices. Review the washer manual and consult a plumber if the protection isn’t clear.

Are check valves required by code everywhere?

Code requirements vary by location. Some jurisdictions may require backflow protection in certain installations, so verify with local building authorities before making changes.