The Holland BPW maintains the public sanitary sewer system relentlessly through cleaning and inspecting. Our Sewer truck is out nearly every work day and sometimes on the weekends and after normal business hours diligently cleaning sanitary sewers. Our 34 sewage lift stations have backup power attachments for generators and our larger, critical lift stations have two independent power feeds to them from different electrical circuits in case of power failures. Our lift stations are also connected to a Supervisory Control and Data Acquisition (SCADA) system that is monitored 24 hours a day, 7 days a week by Wastewater Treatment Plant personnel. The SCADA system will warn us immediately if there is a problem at the lift station such as a power failure, communication failure, high water levels, pump malfunctions, etc. We have many redundant systems in place to prevent failures.
With all of this in place, it is still possible for sewage to back up in the public mains due to root growth in the sewers, or due to lengthy, intense rainfall periods similar to what was experienced in June 2008 and June 2009.
The vast majority of our customers do not experience any problems with sewage backups. However, some properties require the protection of a backwater valve in their private sewer service. These properties were built so that the flood rim of the lowest plumbing fixture (wash tub, floor drain, shower, etc.,) is lower than the cover of the nearest upstream manhole of the public sewer. The backwater valve is designed to automatically close, to prevent sewage from backing up into the building from a blocked public sewer.
Backwater valves are also known as a check valve. 'Backflow preventer' is another term, but that term is usually reserved for devices installed on the drinking water supply lines.
Diagram courtesy of Los Angeles County DPW.
Does the Michigan Plumbing Code require a backwater valve?
Yes. Section 715 of the Michigan Plumbing Code is dedicated to backwater valves on sanitary sewage drainage systems. It states that if there are fixtures below the elevation of the upstream manhole cover, then a backwater valve is required. It goes on to state that if there are fixtures above the upstream manhole cover (main floor or upstairs drains), they SHALL NOT pass through a backwater valve. The reason for not including the upper floors for going through the backwater valve is to protect the basement drains from backups from the upper floor drainage.
If your home was constructed before the Michigan Plumbing Code required a backflow preventer, then you are not required to retrofit your home to install one.
What should I check for?
- If you have any plumbing fixtures lower than the street in front of your house, you may need a backwater valve.
- If the street outside your house goes steeply uphill, you may need a backwater valve.
- If your property already has a backwater valve, it needs to be checked and maintained regularly.
Who is responsible for the installation and maintenance of backwater valves?
Property owners are responsible for the installation and maintenance of backwater valves.
How often do I check the backwater valve and what does it entail?
We recommend that you check and maintain the valve at least once a year. If you have a history of sewer back ups, you should check more often. Checking the newer installations involves a quick removal of the device to check that the valve flap is functioning. The entire mechanism and surrounding pipe should be flushed with a hose during maintenance to clear any accumulated debris from the area. Older installations may be cast iron and more difficult to maintain. For any maintenance questions or issues, please call a licensed plumber.
Can the backwater valve be used as a cleanout?
No! Anytime a sewer snake passes through a backwater valve damage can occur to the valve flapper or the finished seating surface against which the flapper seals.
Where can I get help?
If you think you might need a backwater valve or if you have questions regarding locating or checking the device, the Holland BPW encourages you to contact a licensed plumber. The licensed plumber can evaluate your situation and, if necessary, install a backwater valve.
Where can I get a backwater valve?
Backwater valves are sold through plumbing supply warehouses and sometimes home improvement centers. Contractors should contact their local wholesale plumbing supplier or water and sewer wholesale supplier to purchase the valve.
Do I need a permit for a backwater valve?
Yes, a plumbing permit is required for the installation of a backwater valve. For further information, contact your local building department.
What are some recommendations on backwater valves?
Although the Holland BPW can not endorse any particular product, it is recommended to install a backwater valve that will allow you to gain access to it and maintain it. It is not recommended to install one on the sewer service and bury it without any access point for maintenance! These devices do require maintenance and access to the device is important for proper maintenance and inspection of the operation of the device. If you are making the investment in one of these devices, you want to make sure the device works properly. These devices may not be cheap, but they may prevent thousands of dollars of damages to areas vulnerable to sewage back ups.
One device that can be installed on your underground sewer service is a 
Clean Check manufactured by Rectorseal. This device can be ordered locally at:
- ETNA Supply
- JO Galloup
- Hajoca (Richards Holland)
- TA Gentry
- Shoemaker