What the Supreme Court actually decided
On August 9, 2022 the Missouri Supreme Court issued its decision in Johnson v. Springfield Solar 1, LLC, case number SC99441, holding that the exemption for solar energy systems not held for resale under Section 137.100(10) is unconstitutional.
The reasoning was structural rather than about solar. The court held that the Missouri Constitution delineates the categories of property that may be exempt from taxation, and that the legislature lacked the authority to create an exemption outside those categories.
The State Tax Commission has since issued guidance to assessors on the assessment of solar property following the decision, which tells you the practical consequence reached county assessors rather than staying an abstract point of law.
That does not tell you exactly what your own assessor will do with a residential rooftop array, which is precisely why this page will not tell you either. Ask your county assessor directly how residential solar is being assessed at your address, and get the answer before you commit.
Why so much published material still says otherwise
Most solar guides list a Missouri property tax exemption because the statute is still in the books and because these pages are rarely revisited. A decision from 2022 has simply not propagated through the material homeowners read.
That is worth generalising from. If a guide is wrong about something this checkable, treat its other figures as needing verification too rather than as a reliable baseline.
Ask any installer whether their savings projection assumes a property tax exemption, and ask them to show you the figures without it. An installer working Missouri seriously will already know about the decision.
The same applies to rebates. Missouri investor-owned utilities historically ran solar rebate programmes but these have largely been discontinued, so a rebate line in a quote is something to verify with your utility rather than accept.
What genuinely remains
Net metering does. Missouri's Net Metering and Easy Connection Act, Section 386.890 RSMo, covers qualified net metering units of 100 kW or less, and it applies to regulated utilities, municipal electric utilities and rural electric cooperatives alike.
Standard residential tariffs apply a retail-rate offset for in-period consumption, with year-end surplus reconciled at avoided cost rather than retail. So electricity you use as it is generated, or that offsets consumption within the period, is worth considerably more than a surplus carried to the end of the year.
That points to a system sized to your consumption rather than beyond it. Ask your installer to work from your last twelve months of bills and to show what percentage of your annual usage the proposed system covers.
Ask also how the year-end reconciliation was treated in the projection. A model that carries surplus forward at the retail rate indefinitely is describing something the tariff does not do.
Building the number from confirmed pieces only
Three things people expect in Missouri are either gone or unreliable, and a quote built on any of them overstates your return. The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit.
Utility solar rebates historically existed here but have largely been discontinued. If a rebate appears in a quote, confirm directly with your own utility whether it is currently open, what it pays and whether funding remains, before you sign anything.
And the property tax exemption most guides still list was held unconstitutional by the Missouri Supreme Court on August 9, 2022. Ask your county assessor how residential solar is being assessed at your address rather than assuming an exemption applies.
What does exist is net metering under the Easy Connection Act and the electricity you stop buying. Ask any installer to rebuild the arithmetic from those two things alone, and treat resistance to producing that version as informative in itself.