In Enid, as in most cities, a sewer backs up during heavy rain when storm water gets into the sanitary sewer and fills it beyond what it can carry. Water enters through downspouts or sump pumps tied into the sewer (inflow) and through cracked pipes and joints (infiltration). With nowhere to go, sewage flows back up the house line and out of the lowest drain, usually a basement or floor drain.
Inflow and infiltration, in plain terms
Inflow is rain that goes straight into the sewer through a connection that should not be there: a gutter downspout piped into the sewer line, a sump pump discharging into a floor drain or laundry tub, or an uncapped cleanout in a low spot of the yard.
Infiltration is groundwater that seeps in through cracks, open joints and root holes in sewer pipes, both in private house lines and in public mains. Older clay pipe with many joints lets in the most water.
Sanitary sewers are sized for wastewater from homes, not for rain. When both kinds of extra water arrive during a storm, the pipes run full and the lowest openings connected to them, including your floor drain, become overflow points.
What this looks like in Enid
- The City of Enid notes that the area is subject to flash flooding during or after heavy rain storms.
- The city’s Sanitary Sewer Master Plan reviewed treatment plant records to measure how infiltration and inflow affect its collection system.
- The city has run an annual sanitary sewer video inspection program aimed at finding sources of backups, overflows and infiltration.
- More than half of Enid homes were built before 1970 (Census ACS data), and lines from that era are more likely to be clay with many joints.
How to tell a rain backup from a clog
| Rain-related backup | Clog in your line |
|---|---|
| Happens during or just after heavy rain | Happens in dry weather too |
| Neighbors may have the same problem | Only your house is affected |
| Drains work normally once the storm passes | Drains stay slow until the line is cleared |
| Fix: keep storm water out, backwater valve | Fix: clear the line, check it with a camera |
Both can happen at once. A line partly blocked by roots backs up sooner in a storm than a clean one.
What you can do about it
- Disconnect inflow. Make sure downspouts discharge onto the ground away from the house and that a sump pump discharges outside, not into a floor drain or the sewer.
- Keep the cleanout capped. A missing or broken cap in a low spot lets surface water straight into your line.
- Find leaks in your own line. A camera inspection shows root holes, cracks and open joints where groundwater gets in.
- Consider a backwater valve. Installed on the house sewer line, it lets wastewater out and closes when sewage tries to flow back in. A plumber installs it and a permit is usually needed.
- Check city assistance first. City of Enid code (section 2-6E-6) has provided money toward the cost for customers who install a backflow prevention system on private property, and an amendment changing the program was published in 2026. Ask the city about the current rules before installing.
During a storm backup
- Use as little water as possible until the rain stops and the sewer drains down.
- Keep children and pets out of the area and avoid touching the water.
- If neighbors are affected too, report it to the City of Enid.
- Photograph the damage. Standard homeowner policies often exclude sewer backup unless the coverage was added, so check your policy.
If the floor drain is still slow after the storm has passed, the line likely has a clog as well. Call (580) 555-0123 or see emergency drain cleaning.
Rain and sewer backup questions
Will drain cleaning stop my basement from flooding in storms?
Only if a clog or roots in your own line are part of the problem. If the public sewer is overloaded by storm water, cleaning your line will not stop it; keeping storm water out and a backwater valve are the fixes.
What is a backwater valve?
A valve on the house sewer line with a flap that lets wastewater flow out to the street and closes when sewage tries to flow back toward the house. It needs occasional cleaning to keep working.
Is it illegal to connect a sump pump to the sewer?
Many cities prohibit sending storm water or sump pump water into the sanitary sewer because it causes backups. Check with the City of Enid for the local rule.
Why does the sewer smell after heavy rain?
Rising water in the sewer can push sewer gas up through drains, and a dried-out floor drain trap lets that gas into the house. Pouring water into unused floor drains keeps their traps sealed.