Solar in Monroe County, Illinois: what to know first

GSM Solar can help if you own your home in Monroe County, it is in the Ameren Illinois service territory, and it fits. Not every home here is. Some get power from the City of Waterloo. Some get it from an electric co-op. So look at the top of your power bill first. The company named there decides it.

This page covers what is local to Monroe County: who sells power where, how much power a roof here can make, and who checks the work.

Which power company serves your Monroe County home?

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. At least two other electric utilities serve homes in this county. Here are two that say so on their own websites.

The first is the City of Waterloo. Its electric department says the city furnishes electric service through the City of Waterloo, through the Illinois Municipal Electric Agency. The city also has a power plant the city has owned and run since 1901. If the City of Waterloo sends your power bill, GSM Solar can't help with solar. The city has its own interconnection agreement and net metering policy, so its electric department is the place to ask how solar works on its lines.

The second is the Monroe County Electric Cooperative. A co-op, short for cooperative, is a utility owned by the members it serves. Its history page says it was set up to bring power to rural parts of Monroe, Randolph and St. Clair counties that had none. Today it serves more than 6,700 farms, homes and businesses.

A town name doesn't settle it. The co-op's list of the places it serves includes subdivisions listed under Waterloo, Columbia and Valmeyer, among other towns. So living near Waterloo or Columbia doesn't tell you which utility you have. Your bill does.

If the co-op serves your home, GSM Solar can't help with solar either. Illinois Shines says co-ops and city utilities may limit net metering or credit power a different way. The co-op sets its own steps for solar. A member's new system may not start running until the co-op inspects it. Ask the co-op about the rest.

For every other home in the county, the bill gives the answer. If it names Ameren Illinois, the rest of this page is for you.

How much power can panels make in Monroe County?

We ran PVWatts, a solar model from a national lab, for Waterloo, the county seat. We set it up for one kW of panels on a south-facing roof with no shade. It models about 1,431 kWh a year. This number is about sun only. Your bill decides who serves you.

Those are two different units. A kW is the size of a system: how much power the panels can make at one moment. A kWh is an amount of energy. It is the unit your power bill counts. A bigger system makes about that much for each kW it has.

The model's month by month numbers run highest in July and lowest in December, when the days are shortest. Tap the number above to see every input we used.

A model can't see your roof. East or west roofs make less than a south roof, and so does shade from trees or the house next door. Our page on whether your home is a fit for solar covers roof age, direction and shade. Before you sign anything, the Department of Energy says to get a custom estimate for your own system, from a solar installer.

Who checks the work on a Monroe County home?

Two things get checked: who is allowed to do the work, and whether the work has a local permit.

The state sets the first rule. In Illinois, a company that installs solar must be certified by the ICC before installing, unless you install your own system. ICC is short for the Illinois Commerce Commission. You can look a company up on the ICC list of certified distributed generation installers. Ask the company for the name it is certified under, then check it yourself.

A building permit is the local okay for the work. In a city or village, ask city hall whether solar needs a permit. Outside town limits, ask Monroe County. Ask the company which office will issue yours. Then ask to see the permit before anyone goes up on your roof.

Our guide on how to check a solar company in Illinois covers the state's lists of registered companies and the red flags to watch for.

What comes next if Ameren Illinois serves your home?

Net metering is a credit on your bill for the power your panels send to the grid. In Ameren Illinois territory, a system that starts net metering on or after January 1, 2025 earns credit for supply charges only. Supply is the charge for the power itself. Our guide to net metering in Ameren Illinois explains what that credit covers and what it doesn't.

With solar, you stay a utility customer, responsible for a utility bill. Our guide on whether you still get a utility bill explains why.

Illinois Shines is a state program that provides an incentive for solar projects. Our page on how Illinois Shines works covers what that means for a home. Every number on this site is listed with its source on our data page.

Quick answers

Can GSM Solar help if I live in Waterloo?

Only if your home is in the Ameren Illinois service territory. The City of Waterloo runs its own electric utility. If the city sends your power bill, GSM Solar can't help with solar.

What if the Monroe County Electric Cooperative serves my home?

Then GSM Solar can't help with solar. Co-ops may limit net metering or credit power a different way. Ask the co-op how it handles solar.

How do I tell which utility serves my home?

Look at the top of your power bill. The company named there is your utility. A town name on your mail does not tell you.

Who is allowed to install the system?

A company certified by the Illinois Commerce Commission. The only exception is a homeowner who installs their own system.