When it rains, most of us expect water to run into ditches, storm drains, and creeks. That is where it belongs. What many people do not realize is that rainwater sometimes ends up in the sanitary sewer system instead. When that happens, it creates a real problem for the Ben Davis Conservancy District and for every customer who pays a sewer bill.
The sanitary sewer system is designed to carry wastewater from inside homes and businesses. That means water from toilets, sinks, tubs, showers, and washing machines. It is not designed to carry large amounts of rainwater from outside.
Rainwater can get into the sanitary sewer in a few different ways. Sometimes it comes through cracked pipes or loose joints underground. Sometimes groundwater seeps in around old connections. In other cases, it comes from private property when sump pumps, foundation drains, or downspouts are tied into the wrong line.
Why that matters
Every gallon that enters the sanitary sewer has to be moved, handled, and treated. That includes water that never should have been there in the first place. So when heavy rain pushes extra water into the system, the district is paying to process stormwater as if it were sewage.
That added flow puts stress on pipes, manholes, and pump stations. It also increases treatment costs. In plain English, clean rainwater becomes expensive the moment it enters the wrong pipe. And because the district serves the community as a whole, those costs eventually affect everyone.
Too much inflow can also reduce capacity during storms. That means the system has less room for the wastewater it was actually built to carry. Over time, that leads to more wear on aging infrastructure and makes repairs and rehabilitation more urgent.
How rainwater gets in
- Cracked or aging sewer lines can let groundwater seep into the system.
- Bad joints or broken connections can allow water to enter during wet weather.
- Sump pumps tied to the sanitary sewer send storm-related water into the wrong pipe.
- Downspouts or area drains connected incorrectly can increase flow quickly during a storm.
What homeowners can do
Start by making sure your sump pump discharges outside to a proper stormwater outlet or approved drainage area, not into the sanitary sewer. Check that your downspouts are carrying roof water away from the foundation and not into a sewer cleanout or other sanitary connection. If you are not sure how your property is connected, a licensed plumber can help inspect it.
It is also wise to pay attention to warning signs. If your basement gets wet during storms, if your cleanout seems to overflow, or if your plumber has mentioned unusual sewer connections, it may be worth taking a closer look.
Why the district talks about this so often
Rainwater in the sanitary sewer is not just a technical issue. It affects reliability, system life, and customer cost. That is why the district invests in televising, lining, repairs, and public education. The goal is simple: keep the sanitary sewer focused on sanitary flow, and keep stormwater where it belongs.
When the wrong water gets into the wrong system, everybody pays for it. When the system stays separated, everybody benefits.
If you have questions about your connection or about how the district’s sanitary sewer system works, contact the Ben Davis Conservancy District at (317) 241-2941.
