Wyoming's Stormwater Infrastructure: Understanding What's at Stake

When stormwater drainage came up during Wyoming's 2026 legislative session, it might have sounded like a technical issue best left to engineers and lawmakers. But the numbers tell a different story — and they affect every community, every business, and every taxpayer in the state.

All 99 Wyoming municipalities are required to manage stormwater runoff and compliance. It is not optional. Stormwater is a public safety and infrastructure obligation, and the systems that handle it — pipes, curbs, gutters, detention basins, channels, and treatment facilities — require ongoing maintenance and long-term capital investment to function.

The question has never been whether to fund these systems. The question is how.

The Scale of the Problem

The numbers coming out of Wyoming communities make the challenge clear.

Casper identified 42 priority stormwater projects in its 2013 Stormwater Master Plan totaling $46 million. Only four of those projects have been completed since then. Adding urgent corrugated metal pipe replacements — failures of which have already caused sinkholes in busy roads — brings the total need in today's dollars to $78 million. Casper currently has $20,000 per year in dedicated stormwater funds. At that rate, without accounting for inflation, it would take 3,900 years to address the backlog.

Cody established its stormwater fund in September 2022 and adopted a stormwater study in 2026. Its current 10-year capital plan identifies $29 million in needs against a fiscal year 2026 budget of just over $920,000.

Jackson is working to develop stormwater infrastructure specifically to protect water quality and wildlife habitat, with a goal of eventually removing Flat Creek from the state's list of impaired water bodies.

Evanston has had a stormwater management system in place since 1982 — over 40 years — and amended it in 1984 to include stormwater drainage fees to fund improvements to existing facilities and support new development.

These are not isolated local problems. This is a statewide infrastructure challenge.

How Stormwater Funding Works — And Why It's Complicated

Many Wyoming municipalities fund stormwater management through what are called enterprise funds, or rate-supported service systems. Rather than drawing from general tax revenue, these funds charge user fees based on a property's impact on the stormwater system. Residential and commercial users pay into the fund, and those revenues are dedicated specifically to that system — kept separate from other city funds to ensure the full cost of the service is tracked and resources aren't diverted elsewhere.

Wyoming courts have weighed in on this distinction. In Frank v. City of Cody (1977), the Wyoming Supreme Court ruled that "service charges are not a tax." That legal distinction matters because it affects what kind of approval — if any — is required before a governing body can set or adjust those fees.

That is precisely where the current debate comes in.

The Statutory Conflict

Wyoming statute gives cities and towns authority to manage surface water runoff and regulate rates for that service. But the Surface Water Drainage Utility Act includes a voter approval requirement before a governing body can fund a surface water drainage utility. The Wyoming Legislative Service Office has identified potential conflicts between these two provisions — places where the law appears mandatory in some areas and permissive in others, creating uncertainty for communities trying to plan and fund their systems.

The Wyoming Association of Municipalities has taken the position that broad statutory changes to stormwater funding would be premature until a wider water and wastewater infrastructure study — already authorized by the Legislature — is further along. WAM's goal is a practical solution that protects voter rights where required while preserving workable local tools for communities to manage their systems.

What Comes Next

The Select Water Committee will take up stormwater infrastructure as part of its interim work, with discussion scheduled for May 7 at the Wyoming Water Development Office, 6920 Yellowtail Road, Cheyenne. A livestream will be available at wyoleg.gov.

For more information on the Select Water Committee and its interim work, visit the committee's page on the Wyoming Legislature's website.

As Wyoming Chamber President Dale Steenbergen noted, "There is little doubt that communities across Wyoming have serious needs related to this issue — but the questions of when and how are still omnipresent." Businesses across the state have a stake in how this gets resolved.

[Read Dale's full commentary here.]