Why Sewer Check Valves Must Be Professionally Installed

Sewer Service
July 7, 2014

by David Balkan

sewer check valves

Sewer check valves are installed ever more increasingly as a remedy for city sewer backups. What many people do not realize is that while sewer check valves are relatively simple devices, it takes a skilled professional to install them properly. It is not a job for a handyman, general contractor, or homeowner.

The following are some of the key points for a proper installation to prevent sewer backwater. As simple as these steps may seem, they are frequently overlooked with sometimes disastrous consequences. Also, bear in mind that sewer valves to prevent backwater are completely different than backflow prevention devices for a potable water supply system.

Your 5-Point Sewer Check Valve Installation Guide

1. Proper location for sewer check valves

The single most important factor for installing sewer check valves correctly is proper location. Installing a sewer backwater valve anywhere that seems convenient will not allow for it to serve its purpose. Important to note is that sewer check valves are meant to close automatically before any backwater can escape from the house drain.

sewer check valves


This means that proper installation often requires relocating the house trap, fresh air inlet, and house drain outlets. In most cases, they must be farther away from the front foundation wall to make room for the sewer backwater valve. Sewer check valves installed properly must be the first fitting just inside the foundation wall.

While installing a sewer check valve as described above is more work, doing it any other way will not produce the desired result. If any fittings, such as the house trap, are located on the street side of the check valve, backwater can leak out. This can occur from trap plugs blowing off due to being under backwater pressure.

Sewer backwater can also pour out if the trap plugs or existing pipes are not watertight. Once again that is why it is vitally important to have sewer check valves installed at the correct location.

2. Proper pitch for the pipe must be available

As sewer check valves slow the flow of wastewater from the house drain, the proper pitch must be available. The pitch of a pipe is also referred to as the slope of a pipe. If the pitch of the pipe is very close, clogs and stoppages can form inside the check valve.

In the case of automatic knife-edged flood gate valves, even more care must be taken when considering the pitch on the pipe. This is yet another reason that only trusted and licensed plumbers should perform such installations. Learn more about proper drain pipe installation by reading about the slope of a sewer or drain pipe.

3. Knowing which type of sewer valve to install

Different sewer backwater problems require different solutions. Sewer check valves are specifically designed when a public sewer backs up for a relatively short period of time. This is because sewer check valves do not stop backwater 100% – they only greatly reduce it.

Inside of a sewer check valve body.

When public sewers remain surcharged over a long period an automatic flood gate valve may be a better choice. While considerably more expensive, they stop backwater 100%.

Another issue to consider is that when any backwater valve is closed, waste and rainwater cannot flow out of the house drain. Therefore in many multifamily or large commercial buildings, a sewer backwater device may not be advisable. A careful site inspection by a knowledgeable plumber is strongly advised before committing to any installation.

4. Sewer check valves must be accessible for maintenance

Another important factor about sewer check valves is that they require regular cleaning about twice a year. But even that varies depending on factors such as the type of building and use inside the building. For instance, a restaurant would require more frequent cleaning due to possible accumulation of grease.

A sewer access pit that has not been cemented in place yet.

For this reason, sewer check valves must not only be exposed but also easily accessible. In some cases, installers and property owners have been known to cement over or cover sewer check valves. This could be for aesthetic reasons, or simply out of ignorance. The result is a non-functioning backwater device and a source of stoppages from a lack of maintenance.

5. When is a clean-out a good idea?

Sewer check valves can be damaged by a sewer cleaning machine. This can occur if a sewer cleaner attempts to pass through the check valve by way of the house trap. If a house sewer must be cleaned it is suggested the snake be inserted through the top of the check valve. This can be done by removing the top plate. This takes only a minute as four bolts hold the top plate on typical sewer check valves.

Access pipe for sewer cleaning and maintenance.

In the case of automatic flood gate valves, a clean-out on the street side of the device is required by the manufacturer. If a clean out is not installed the device can be damaged, and the warranty will be voided. There are so many reasons sewer backwater valves should be installed by licensed plumbing firms, this is yet another.

Knowing when to install a clean-out may seem like a minor detail. However, when a warranty can be legally voided on an expensive plumbing device, properly installing a clean-out should be duly noted. If you have further questions, read a great 9-point sewer backflow preventer Q&A guide.

Licensed professionals install sewer check valves

A licensed professional refers to a Licensed Master Plumber who is properly insured and bonded. It does not refer to a home improvement contractor or a handyman. License status in NYC can be easily verified on the NYC Department of Buildings website, as can proper insurance being in place. When you are trusting someone to protect your home and family from being exposed to sewer water, take no chances. Hiring a licensed and experienced plumber ensures a long-lasting and properly functioning plumbing installation.

About Balkan Sewer And Water Main Service

The Balkan Team provides expert sewer and water main repairs and replacements. We are experts in all types of NYC underground plumbing. Balkan Sewer And Water Main Service was founded in 1952. Since its inception, the foundation of the company has been based upon integrity and honesty in all of our dealings. That solid foundation has enabled us to thrive in every economic climate.

The year 2022 actually marked our 70th consecutive year in business. As we have grown, we have become increasingly dependent upon a “Team First” approach.

A Team First Approach Ensures High Standards

What helps ensure a continuation of our high standards, overall integrity, and high company morale, is that same team approach. Complete client satisfaction has always been the number one goal at Balkan Sewer And Water Main. That is why we are NYC’s largest and most trusted sewer and water main service in New York City. Simply put, if it’s plumbing, and it’s underground, we do it. For over 70 years, and for over 90,000 New Yorkers to date, Balkan is “The Team You Trust”.

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David Balkan

David Balkan is the CEO of Balkan Sewer And Water Main, the largest and most trusted service in New York City. David is extremely active in various NYC plumber organizations being the Chairman of the Subsurface Committee in the Master Plumbers Council, and Vice President of the Subsurface Plumbers Association. In addition David’s expertise is respected by officials of New York City agencies such as the NYC DEP, NYC DOB, and the NYC DOT. He frequently provides valuable input on a variety of industry related matters.

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