One document, thirty days
For systems of ten kilowatts or less the application process uses an all-in-one document that includes a simple interconnection request, simple procedures and a brief set of terms and conditions. That is the Easy Connection part of the Net Metering and Easy Connection Act.
The utility is required to review and respond within 30 days of receipt for systems of ten kilowatts or less. For all other systems up to 100 kilowatts the response window is 90 days.
So the size of your system determines which timeline you are on, which is worth knowing if a design sits close to ten kilowatts. Ask your installer which route the proposed system falls into and why.
Ask for the date the complete application was submitted, since the clock runs from receipt. Then you know when a response is due rather than relying on a general assurance that things are progressing.
It applies whoever bills you
The law applies to all regulated electric utilities, to municipal electric utilities and to rural electric cooperatives, which are required by the law to adopt policies establishing a simple contract to be used for interconnection and net metering.
That is unusual. In most states municipal utilities and cooperatives sit outside the statewide rule and set entirely their own terms, which is why solar advice travels so badly elsewhere. In Missouri the framework reaches everyone.
Each utility still adopts its own policies under the law, so ask yours for the policy in writing and confirm how exported electricity is credited, how the year-end reconciliation works and what size limit applies.
Ask also whether there is an interconnection fee and what inspection or documentation is required, so that the timeline you were quoted reflects the whole process rather than the easy half of it.
What the crediting means for your design
Standard residential tariffs apply a retail-rate offset for in-period consumption, with year-end surplus reconciled at avoided cost rather than at the retail rate.
So a kilowatt hour that offsets your own consumption within the period is worth the retail rate, while one that survives to the annual reconciliation is worth considerably less. That argues for sizing to consumption rather than beyond it.
Ask your installer to work from your last twelve months of bills, to show what percentage of your annual usage the system covers, and to state how the year-end reconciliation was treated in the projection.
Finally, do not assume a property tax exemption. The Missouri Supreme Court held on August 9, 2022 in Johnson v. Springfield Solar 1, LLC that the exemption under Section 137.100(10) is unconstitutional, so ask your county assessor how residential solar is assessed at your address.
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.