What it means
Unlike gravity sewers, force mains stay pressurized when pumps run. They can experience air binding, corrosion, pressure surges, leaks, and odor issues. Their condition is harder to inspect because they are full and pressurized.
What operators watch
- Air release valves and surge control can be important.
- Pump operation affects force-main pressure and velocity.
- Breaks can release wastewater under pressure and require fast isolation.
Common exam traps
- Treating force mains like gravity sewers.
- Ignoring pressure transients and air pockets.
- Forgetting corrosion and odor potential in long detention lines.
Field example
A lift station with high discharge pressure and low flow may have a partially blocked force main or valve issue.
