🏡 Unlocking the Bonus Unit: How St. Louis’s Zoning Makeover Could Mean Big Gains for Homeowners & Investors

For the first time in decades, the city of St. Louis is rewriting its zoning playbook — and this change could quietly reshape how we live, build, and invest in the Gateway City.

This isn’t just bureaucratic shuffle. It might be a property-value accelerator in plain sight.

What’s Changing

In July 2025, the Board of Aldermen passed Board Bill 60 (BB 60), an ordinance effective September 29, 2025, which amends the Zoning Code to define, permit, and regulate accessory dwelling units (ADUs). Specifically, it allows both attached and detached ADUs by-right in all residential zones in the City — no special variance needed just to add a little rental unit or guest house.

Meanwhile, in February 2025 the city adopted the Strategic Land Use Plan (SLUP), which sets the block-by-block vision for future land-use, density, mixed-use, and housing flexibility in the City.

Together, BB 60 + the SLUP form the policy backbone of the city’s real estate pivot: more housing types, more flexibility, and more potential opportunity.

In practical terms: homeowners may soon have more flexibility to use their property the way life actually works today — whether that means multigenerational living, a home office with a separate entrance, a rentable backyard cottage, or a built-in investment hedge.

Why It Matters

For Sellers:

If your property sits on a lot large enough for an ADU or conversion, that’s an instant selling point. You can market: “ADU-eligible lot” rather than just “big backyard.” Buyers love future potential, especially when zoning supports it.

For Buyers:

ADUs open doors (literally and financially). You can offset your mortgage with rental income, build a private space for family members, or future-proof your home for aging-in-place — all while living in neighborhoods once constrained by single-family-only zoning.

For Investors:

This is your green light to re-imagine the St. Louis investment model. Small infill projects, cottage conversions, creative rehabs now have new legs. Investors who understand these zoning shifts ahead of the curve will be the ones buying tomorrow’s bargains today.

The Bigger Picture

St. Louis isn’t acting in isolation. Cities like Minneapolis, Portland, and Kansas City have already embraced more flexible zoning to address housing shortages. But the difference here? The City of St. Louis’s neighborhoods are filled with historic charm and large urban lots — making it a perfect match for the ADU trend if done thoughtfully. Additional context: the SLUP lays the foundation, and zoning reform (like BB 60) carries the action.

With inventory still tight and prices slowly creeping upward across the metro, the timing couldn’t be better. Supply relief and a potential value boost? That’s real-estate speak for “win–win.”

What Homeowners Should Do Now

1. Check your zoning. Use the City’s Planning & Urban Design Agency site to look up your property classification and lot dimensions to see if ADU is viable.
2. Talk to a pro. Before you add a unit or start dreaming about rental income, consult your REALTOR® and a local zoning/planning expert.
3. Think long-term value. Even if you’re not ready to build the ADU now, you can note “ADU-eligible” in your future listing — it becomes a hook for buyers.
4. Stay tuned. The zoning code overhaul (via ZOUP) is ongoing, and new draft maps are expected in the next 12–18 months under the SLUP’s implementation framework.

The Bottom Line

The next wave of real-estate opportunity in St. Louis may not come from the newest subdivision — but from backyards and garages of homes already here.
For homeowners: it’s a chance to rethink space.
For investors: a reason to re-run the math.
And for the city? Maybe, just maybe, a new chapter in keeping St. Louis’s historic neighborhoods alive, adaptable, and full of possibility.

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