Solar in St. Clair County, Illinois: what to know first

GSM Solar can help a St. Clair County home in the Ameren Illinois service territory, if the home fits. You need to own it. The roof needs to be in good shape, with sun on it. Some towns here run their own power company, and some homes get power from a co-op. GSM Solar can't help those homes.

So the first thing to find out is who sends your power bill.

Which power company serves your part of St. Clair County?

GSM Solar works only with homes in the Ameren Illinois service territory. GSM Solar is not affiliated with Ameren Illinois, any co-op or any city utility, and none of them runs or backs its offer. Not every home in St. Clair County is in it.

Mascoutah and Freeburg both say on their own websites that they run their own electric systems. In Mascoutah, the city runs its own locally owned electric service. In Freeburg, the village has its own power plant and provides electric service to village homes and businesses. If your bill comes from either one, GSM Solar can't help with solar right now.

Some homes, in the country and in some subdivisions, get power from an electric cooperative, called a co-op. Three co-ops name St. Clair County on their own websites, and a fourth lists subdivisions it serves under St. Clair County towns:

• Southwestern Electric Cooperative serves parts of St. Clair County, among other counties in southwestern Illinois.
• Egyptian Electric Cooperative Association serves portions of Saint Clair County, among other counties in southern Illinois.
• Clinton County Electric Cooperative serves parts of St. Clair County, along with Clinton, Fayette, Madison, Marion and Washington counties.
• Monroe County Electric Cooperative's website shows subdivisions it serves listed under Belleville, Freeburg and Millstadt.

That last one is a good reason not to guess. The name of the nearest town does not settle who your power company is. Look at the top of your power bill instead. The company named there is your utility.

If a co-op or a city utility sends your bill, the rules on this site may not match yours. Illinois Shines says co-ops and city utilities may limit net metering or credit power a different way. Your utility can tell you how it handles solar.

In the Ameren Illinois service territory, systems that start net metering on or after January 1, 2025 get credit for supply charges only. Supply is the charge for the power itself. Our net metering guide explains what that credit covers. With solar, you stay a utility customer, responsible for a utility bill.

How much power do panels make near Belleville?

PVWatts is a model built at a national lab. You give it a place, a roof direction and a slope. It gives back how much power panels would make there in a typical year.

For one kW of panels on a south-facing roof near Belleville, PVWatts models about 1,418 kWh a year. A kW is the size of a system. A kWh is an amount of energy, the unit your power bill counts. A bigger system makes about that much for each kW it has.

That is a little more than the same model gives for Edwardsville, about 1,395 kWh a year, or Marion, about 1,407 kWh a year. Near Belleville, the model shows the most power in June and the least in November and December.

A model is not a measurement. It can't see the tree in your yard or the vent pipe on your roof. East or west roofs make less, and so does shade. Before you sign anything, get a custom estimate for your own system, from a solar installer.

Who handles the solar permit in your town?

Belleville, O'Fallon, Fairview Heights and Swansea post their own permit rules online. Here is what each one says.

Belleville asks for permits through the city's Health, Housing & Building Department for any improvement to private property inside city limits. That department also keeps a list of electrical contractors the city has licensed for solar jobs. If you live in Belleville, ask whether the electrician on your job is on it.

O'Fallon asks for a building permit when solar work changes the structure. If the work makes no structural changes, it can go on an electrical permit alone.

Fairview Heights asks for a building permit from the city's Building Permits and Inspections Department before improvements or alterations to a property.

Swansea's rules are the most detailed of the four. The village requires a building permit for every home solar install, before any work starts. It wants an installer who is active in the Illinois Commerce Commission's utility company database. The roof plan has to show how many roof layers the house has and about when it was last roofed. The application also needs an analysis or drawing from an Illinois licensed structural engineer.

Our guide on how to check a solar company covers what to look up about an installer before you sign.

If your home is outside city or village limits, ask St. Clair County what it needs for your address before work starts.

What can you check before anyone comes out?

You can check these from home:

• The company named at the top of your power bill.
• Whether your home is inside city or village limits, and which town's permit rules apply.
• How many layers of roofing are on the house, and about when it was last roofed. Swansea asks for both, and both are worth knowing anywhere.
• Which side of the roof faces south, and where shade falls in the morning, at midday and late in the day.

Our page on whether your home is a fit goes through the roof and the sun in more depth. Illinois Shines is a state program that provides an incentive for solar projects. See how Illinois Shines works. Every number on this page is listed with its source on our data page.

Quick answers

Can GSM Solar help my home in St. Clair County?

Yes, if your home is in the Ameren Illinois service territory and it fits: you own it, and the roof is in good shape with sun on it. If the City of Mascoutah, the Village of Freeburg or an electric co-op sends your bill, GSM Solar can't help with solar right now.

How do I know which power company serves my home?

Look at the top of your power bill. The name of the nearest town is not enough. A co-op serves some subdivisions it lists under Belleville, Freeburg and Millstadt.

Do I need a permit for solar in St. Clair County?

Ask your city or village first. Belleville asks for permits for any improvement to private property in city limits. Fairview Heights and Swansea say the permit comes before the work. O'Fallon uses a building permit or an electrical permit, depending on the job. Outside town limits, ask St. Clair County.

Does a co-op or city utility handle solar the same way?

Not always. Illinois Shines says co-ops and city utilities may limit net metering or credit power a different way. Ask yours how it handles solar.