Drinking water has a water bill. Sewer service has a sewer bill. Storm drainage, the third system every town depends on, has nothing. No bill, no fund, no line item with its name on it. The ditches, culverts, storm drains and outfalls that carry rain away from your street are the orphan of small-town infrastructure, and it shows.

This article is about what happens when that orphan system fails, and about a connection most people never make: in communities that rely on septic systems, bad storm drainage doesn’t just flood streets. It quietly destroys the way those homes handle sewage.

The Utility Nobody Pays For

In small municipalities, storm drainage was never set up like a real utility. For most of American history it was treated as a side job of the road department, pipes under the streets with no funding source of their own. That habit never changed. Nationwide, of the roughly 7,500 communities large enough to need a federal stormwater permit, only about 1,800 have any dedicated stormwater funding at all. Everyone else pays for drainage out of the general fund, which means drainage competes with police cars, snow plows and everything else, and usually loses. Small rural towns are the least likely of all to have a dedicated stormwater fee.

The results are what you would expect. On the 2025 national infrastructure report card, stormwater received a D, tied for the lowest grade of any category measured. The EPA’s latest national survey puts stormwater needs at $115.3 billion over 20 years, and the Water Environment Federation estimates the annual funding gap for permitted communities alone at $8 billion a year. Federal loan and grant programs that do exist for stormwater pay for construction, not for operations and maintenance. Nobody funds ditch cleaning. Ditch cleaning is exactly what small towns need most.

The Rain these Systems were built for No Longer Exists

A culvert installed in 1955 was sized for the storms of 1955. Those storms are gone, replaced by bigger ones.

This is not a claim from a distant think tank. It comes from the Illinois State Climatologist’s office at the Illinois State Water Survey. Their data shows total annual precipitation in Illinois has increased by about 5 inches over the past 120 years, a 12 to 15 percent rise. More important than the total is the intensity: the number of days with 2 or more inches of rain has increased 40 percent since the beginning of the 20th century. Across the Midwest, the National Climate Assessment found the most intense rainfall events have grown 45 percent stronger over recent decades. The Illinois DNR reports the state’s precipitation increase far exceeds the national average.

Flooding is already the costliest weather hazard in Illinois, with urban flooding alone causing at least $2.4 billion in documented damage between 2007 and 2014. When an intense storm hits, runoff spikes fast and overwhelms storm drains, ditches and channels, flooding areas well outside mapped flood zones. In a small town, that means water standing in yards, alleys and fields for days because the undersized culvert at the end of the block cannot pass it and nobody has cleaned the ditch since the Clinton administration.

Standing water is annoying. What it does underground is worse.

What Standing Water does to a Septic System

Remember from the last article that many small Illinois communities, including more than 200 with no public sewers at all, depend on septic systems. Here is how one works. Waste flows to a buried tank where solids settle out. The liquid then moves to a drain field, a set of perforated pipes buried in the yard. The liquid seeps out of those pipes and filters down through several feet of soil. It is the soil itself that finishes the treatment, straining out bacteria before the water reaches groundwater.

That design has one absolute requirement: the soil under the drain field must be dry enough to accept water. A septic system does not treat anything. The dirt does. Take away dry soil and you have taken away the treatment process.

Now connect the two problems. When a town’s drainage fails, water that should have left the neighborhood in hours instead soaks into the ground for days. The soil saturates. The water table rises. Every septic drain field sitting in that ground stops working at once. The failure runs in both directions.

The EPA is blunt about the first direction: when soil is saturated, wastewater from a septic system “will not be treated and will become a source of pollution”, seeping upward or sideways instead of filtering down.

The second direction is the one homeowners notice. A rain-soaked drain field cannot accept the liquid coming from the house, so sewage backs up through the lowest drain, which is usually in the basement. University extension services warn that high groundwater can even pour into the tank itself through its lids and pipe connections, and can shift or damage the tank and lines, turning one wet season into a repair bill.

Notice whose fault this is not. The homeowner did nothing wrong. The tank was pumped, the system was maintained and it failed anyway, because the ground it depends on stayed wet. The cause was on the public side of the property line: a plugged culvert, a silted ditch, a drainage system with no budget. And the fix is brutal for the family involved. A drain field ruined by repeated saturation has to be replaced, a project that costs thousands of dollars per household, with no grant program knocking on the door. The town’s cheapest deferred maintenance becomes the resident’s most expensive surprise.

In unsewered communities the picture is uglier still. The IEPA has documented that many of these towns have old “wildcat” pipes discharging waste directly into surface waters, which in practice means the roadside ditch is carrying both stormwater and sewage. When that ditch clogs or backs up in a heavy rain, the water standing in yards is not just rainwater. The state’s own health guidance connects intense rainfall and flooding to contamination from sewage overflow, and the people wading through it are the residents of the smallest, poorest towns in Illinois.

The Cheapest System to Maintain, the Easiest to Ignore

Here is the bitter irony of storm drainage. Of the three systems in this series, it is by far the cheapest to keep working. Ditches need mowing and regrading. Culverts need clearing and occasional replacement. None of it requires a treatment plant or a certified operator. A few thousand dollars a year of steady maintenance prevents most of the damage described above.

But because there is no drainage bill, there is no drainage budget, and work that is easy to defer gets deferred forever. The cost does not disappear when a village skips ditch maintenance. It moves. It moves into flooded basements, into failed drain fields, into contaminated yards and into emergency repairs that cost ten times what the mowing would have. Deferring drainage maintenance is not saving money. It is billing the future, and sending the invoice to whichever household happens to sit at the low spot.

Next: The Problem in the Solutions

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