- Flooding and Stormwater Management
- Stormwater Management
- Sanitary Sewer Overflows
Sanitary Sewer Overflows
Why do manholes overflow?
Manholes are a way to access sanitary sewer mains that are below streets or alleys. Manholes overflow because the sewer mains have excessive amounts of rain water entering the system. The rain water enters the main from a variety of sources including:
- Yard drains
- Roof drains connecting to sewer lines
- Basement sump pumps
- Missing clean-out caps
- Damaged and broken pipes due to aging or tree roots
It is important to remember that federal, state and local government agencies do not allow ground water or rainwater to enter sanitary sewer lines. All rainwater runoffs must be connected to storm sewer mains which are designed for this purpose only.
Sanitary Sewers vs. Storm Sewers
Sanitary sewers collect and convey wastewater (showers, kitchens, washers, bathrooms, sinks, etc.) to a sewage treatment plant. It is important to understand that sanitary sewer lines are a completely different set of pipes from storm sewer lines. Sanitary sewers have limited capacities and are not designed to dispose of stormwater (i.e. rainwater).
In Highland Park, an independent system of storm sewer lines are used to transport stormwater to creeks with no treatment. Stormwater inlets along roadways are constructed to receive rainwater.
All storm sewer inlets ultimately enter natural water sources.
Avoiding Sewer Overflows
The Town has developed an aggressive program to eliminate sanitary sewer overflows. This program is coordinated with the Texas Commission on Environmental Quality (TCEQ). The Town continues to mitigate sewer overflows by :
- Replacing aged pipes
- Reconstructing manholes
- Cleaning sewer lines within the Town right of way
The Town’s program has and continues to reduce number, frequency, and volume of sewer overflows.
How You Can Help
- Check all yard drains to ensure they drain into the street or alley
- Check the sewer clean-out caps to see if they secured. If missing, call the Engineering department and we will deliver a cap free of charge
- If you have a basement, make sure the pumps are not connected to your sewer pipe
- Make sure your roof drains are not connected to sewer pipes
Illicit Discharge Detection and Elimination (IDDE) Field Investigation Guide 2011 (PDF)