What is a backwater valve floor drain and do you need one?

Plumbing problems can be quite a hassle, especially when they arise from blocked drains. When your home’s main sewage line becomes clogged, the backed-up sewage usually finds a way out through the lowest drain, which is usually the basement floor drain. However, this untidy condition can be avoided by installing a basic plumbing device. The best part? You might even be able to install it yourself.

This essential device is called a backwater valve. Let’s explore what it is, how it works, and why you might need one.

What is a backwater valve?

The way drains are designed is that sewage flows downhill into the sanitary sewer. A backwater valve, when attached to a floor drain, has a one-way gate that opens up every time sewage goes down the drain.

However, when your sewer line gets blocked or clogged, that sewage backs up towards the floor drain and pushes against that gate in the opposite direction. This automatically shuts the gate, preventing the sewage from entering your home.

People often mistake backwater valves for backflow preventers. However, the two devices differ in their primary function.

Backwater valves are attached to floor drains to prevent backed-up sewage from entering your home. Backflow preventers are attached to water supply pipes, and their purpose is to ensure water flows only in one direction, towards your home. They prevent water from getting contaminated and re-entering the main water supply, thereby reducing the risk of contaminating the water supply.

Is a backwater valve necessary?

A backwater valve is necessary and, in most places, is a part of the code. So before you run off to the hardware store to buy one, it may be a good idea to remove your floor drain cover and check if there already is one in place.

You may want to check with the officials at your city’s building inspection department if you see that one isn’t in place. It might just be the case that sewage backups in your community are quite unlikely.In any case, installing a backwater valve is a fairly easy process that you could do yourself. While a professional installation by a certified plumber could cost anywhere between the national average of $300 to a high of $1,000, including labor, the part in itself should not cost you more than $100. The entire process should not take you more than fifteen minutes.

What you’ll need

In addition to a backwater valve, you will need the following tools.

1. A screwdriver
2. Locking pliers
3. A wire brush or old toothbrush
4. Pipe thread sealant for use on plastics

The process

1. Remove the Drain Cover. Unscrew the basement floor drain cover and clean the thread on it with a wire brush or old toothbrush.
2. Apply Sealant. The valve has two parts: a ball and an insert. Apply the pipe thread sealant on the threads of the valve insert.
3. Position the Valve. The ball must be dripped into the sewer and the inlet must be screwed into place. The easy way to do this is to use a rubber bush at least 2 inches wide. After this, hold it with the pliers to screw the insert in place.
4. Test the Seal. The ball remains floating in the sewer until the sewage levels rise. Then, the ball rises towards the insert and seals tightly against it, effectively preventing sewage from entering your home. 

Conclusion

A backwater valve is a simple yet crucial addition to any home’s plumbing system, acting as a check valve to protect against sewage backups. Installing one ensures your basement remains free from unexpected floods caused by clogged drain pipes. Given its affordability and ease of installation, adding a backwater valve is a wise investment in your home’s safety and peace of mind.

Written by Narayan Shrouthy. July 20, 2022

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.