Sewer Cleaning

The Township DPW operates a sewer jet truck and CCTV trucks every year during the spring, summer, and fall seasons. These crews are cleaning our sanitary sewer system and inspecting them for any defects that need to be repaired in order to prolong the life of our infrastructure. While DPW is working in the sewer system, please keep in mind:

• It is possible that water from your internal plumbing may blowback into your home. If you see the trucks in your area, keep your toilet seats down and plug any washtubs in your basement.
• Water back-ups from our sewer jet truck are not caused by the PSI output on the truck. It is caused by trapped air which is not able to escape through your vent pipes. As the air is being pulled through the pipe, it can push water behind it and it can end up in your home if your vents are plugged.
• According to ACT 222 of 1996, you have 45 days from the time of a backup to make claim to the Township for damages and you must prove that there was a defect in the public sewer infrastructure that the Township knew about and did not fix.

Reasons for Blowback During Sewer Maintenance Cleaning

During the sewer maintenance cleaning process, a jet nozzle and hose are inserted into a manhole, and water pressure is then used to propel the nozzle and hose up the main to the next manhole. Then, the jet nozzle is slowly pulled back to clean the inside of the main and collect the debris at the downstream manhole for removal. This process is used to remove accumulations of roots, grease, sludge, and grit that have built up over time. Through this maintenance effort, the chance of sewer backups is decreased and capacity of flow is restored to the main.

Water is pumped through the jet nozzle at a rate of 50-65 gallons per minute and at 1000-2000 pounds per square inch (psi). During this cleaning process, while the nozzle is propelling itself up the line, a negative pressure is created ahead of the nozzle while a positive pressure is created on the back side of the nozzle. The amount of positive or negative pressure created by the nozzle varies with the pump pressure and water volume used to propel the hose up the line. As the nozzle moves through the line, it passes house laterals in a fraction of a second, causing a rapid change from negative to positive pressure. This positive pressure pushes back into the service lateral line. If there is nowhere for the positive pressure to go (through a properly vented stack) then it will force its way out through the plumbing fixtures or floor drain, thereby creating blowback. Blowback is an eruption of air and water discharging incorrectly from a plumbing fixture drain.

Blowback can be caused by a plugged vent stack, or inadequately designed plumbing. If you have a blowback problem, please notify the Grand Blanc Township Department of Public Works. We will record your name and address and will attempt to clean the line at minimum pressures and water volume in the future, even though sewer cleaning efficiency and effectiveness are reduced

How to Prevent Backups In Your Lateral and in the Township Main

• Dispose of Grease Properly: Cooking oil should be poured into a heat-resistant container and disposed of properly, after it cools off, not in the drain. Washing grease down the drain with hot water is unsatisfactory. As the grease cools off, it will solidify either in the drain, the property owner's line, or in the main sewer causing the line to constrict and eventually clog.
• Dispose of Paper Products Properly: Paper towels, disposable (and cloth) diapers and feminine products can cause a great deal of trouble in the property owner's lateral as well as in the city main. These products do not deteriorate quickly, as bathroom tissue does, so do not put them down the drain or toilet.
• Replace Your Line with New Plastic Pipe: One way to prevent tree roots from entering your line is to replace your line and tap with new plastic pipe. If you have continuing problems with tree roots in your lateral, you may have to have the roots cut periodically.
• Correct Illegal Plumbing Connections: Do not connect French drains, sump pumps and other flood control systems to your sanitary sewer. It is illegal, and debris and silt will clog your line. Consult a plumber to correct any pre-existing illegal connections. French drains are common drainage systems, primarily used to prevent ground and surface water from penetrating or damaging building foundations.
• Install a Backwater Prevention Valve: A backwater valve is a fixture installed into a sewer line, and sometimes into a drain line, in the basement of your home or business to prevent sewer backflows. A properly installed and maintained backwater valve allows sewage to go out, but not to come back in. Property owners are responsible for the installation and maintenance of backwater valves. The cost to install one depends on the type of plumbing in the building and the difficulty of installation. Check with a qualified plumber.