The District offers free inspections of private sewer laterals to determine if an anti-flooding device is needed to protect a home or business from un-welcome sewer backups.
A private sewer lateral or house lateral is the pipeline that connects your drains to the District’s wastewater collection pipeline, usually located in the street or near the property line. Your private sewer lateral is owned and maintained by you as a property owner, including any part that extends into the street or public right of way.
A District audit designated premises as potentially “at risk” if they have one or more of the following conditions:
- Topography and location of sewer lines being likely to cause backups due to steepness of slopes or pipelines serving steep slopes meeting sewer lines serving flat areas
- Buildings where there is a plumbing drain outlet at an elevation that is 48” or less above the ground surface of the next upstream manhole
If you have either of these conditions, a blockage in the main line could result in sewage flowing backward into your private sewer lateral. The backup could be discharged through a clean-out in your private sewer lateral, or in the worst case, back up into the lowest drain in your home.
Blockages and sewer backups are an unfortunate, but possible, event in the operation of a wastewater system. Several factors contribute to the cause of a sewer backup. Some are the result of behavioral and environmental factors, including:
- Tree roots
- Customer disposal of Fats, Oil, and Grease down household drains
- Topography and slope of the pipelines and the properties served
Other factors relate to characteristics of the system such as:
- Age and deterioration of sewer pipelines
- Multiple connections to a single lateral
- Absence of outdoor sewer backflow prevention devices on individual properties
Property owners can protect their property by installing an outside clean-out equipped with an approved anti-flooding device. This clean-out and anti-flooding device should be installed as close as possible to the outside of the foundation wall. The clean-out should extend approximately three inches above the finished grade of the ground so that access can easily be obtained.
There are several types of anti-flooding devices; each, if used properly will protect property against sewer back ups. They are:
- One way directional flow (Clapper Valve) – this is the most certain form of protection but requires additional maintenance effort. This device should be installed in a vault for easy access.
- Pop off cap – this can be installed on an outside clean-out and must not have any restraining clamps that prevent the cap from easy removal. The clean-out needs to be approximately three inches above the surface of the ground and exposed for easy access.
- Spring loaded relief valve – this is installed on the outside of the clean-out. The clean-out must have a threaded coupling into which the relief valve can be installed. This should only be installed on a cleanout that has the appropriate height and location, as close as possible to the outside of the foundation wall and approximately three inches above the level of the ground, to ensure the relief valve will open freely.
An anti-flooding device needs to be kept clear from debris that might prevent it from working properly, including pine needles that might block access. At least twice a year check to make sure it is in proper working condition.
If you want to install an anti-flooding device yourself, you will have to dig a small hole to expose your sewer lateral, cut and remove a small portion of the pipeline, and install new pipe and fittings for the outside clean-out and anti-flooding device components. If you don’t feel comfortable doing the work yourself, the District recommends that you hire a licensed plumber.
It is the property owner’s responsibility to maintain their private sewer service lateral and protect themselves from damages that could potentially occur from a sewer backup. Therefore any customer that has been identified as at risk for a sewer backup, who chooses not to install an anti-flooding device, is responsible for any and all damages resulting from a sewer backup incident.
