What Is In-Law Suite?
An in-law suite is a self-contained unit—bedroom, bath, kitchen or kitchenette, separate entrance. Often in a basement or addition. You live upstairs, rent the suite. In St. Louis, a 1,200 sq ft ranch with a 600 sq ft basement suite rents for $950/month—the owner's PITI is $1,400, so he pays $450 to live there. Zoning and building-permit rules apply. Some areas allow them by right; others need a zoning-variance. Get a certificate-of-occupancy before renting.
An in-law suite is a secondary living unit within or attached to a single-family home—typically with its own entrance, bedroom, bath, and sometimes a kitchen. It's a common house-hacking strategy for generating rental-income while you live in the main unit.
At a Glance
- What it is: Secondary unit with bedroom, bath, kitchen, entrance
- Common locations: Basement, addition, converted garage
- Why it matters: Rental-income; house-hacking
- Legal: Zoning, building-permit, certificate-of-occupancy
- Use it for: House-hacking; cash-flow
How It Works
What makes it a suite. Separate entrance. At least one bedroom, one bath. Kitchen or kitchenette (sink, fridge, microwave—some jurisdictions require a stove). Sound separation from the main unit. Egress windows if below grade. Meets local habitability codes.
Zoning. Some cities allow in-law-suites by right in single-family zones. Others require a special permit or zoning-variance. Check before you buy or build.
Permits. Converting a basement or building an addition requires a building-permit. Electrical, plumbing, egress—all must pass inspection. Final inspection triggers the certificate-of-occupancy. Don't rent without it.
Rent potential. Basement suites often rent for 60–75% of what a comparable above-grade unit would fetch. A 2-bed main unit at $1,400 might have a 1-bed suite at $850–$1,050. Location and condition drive the number.
Real-World Example
Sophia in Denver. She bought a 1,400 sq ft ranch with an unfinished 700 sq ft basement. Spent $45,000 on the conversion: bedroom, full bath, kitchenette, separate entrance, egress window. Building-permit and certificate-of-occupancy in hand. She lives upstairs, rents the suite for $1,200/month. Her PITI is $1,850. Net housing cost: $650. She could've rented a similar apartment for $1,400. She's building equity and cash-flowing $550/month in savings. The suite paid for itself in about 6 years on cash-flow alone—faster with appreciation.
Pros & Cons
- Rental-income offsets mortgage
- Owner-occupied-financing rates
- Lower cost than buying a duplex
- Common in many markets
- Zoning and permit hurdles
- Construction cost and timeline
- Less privacy than a duplex
- Basement units rent for less
Watch Out
- Unpermitted suites: If the suite wasn't permitted, you may need to bring it to code—expensive. Get a property-inspection and check permits before buying.
- Insurance: Tell your insurer you have a tenant; you may need different coverage.
- Egress: Below-grade bedrooms need egress windows meeting code—non-negotiable for safety.
Ask an Investor
The Takeaway
An in-law-suite is a powerful house-hacking tool. Get zoning and building-permit clearance before you build. Certificate-of-occupancy before you rent. Then enjoy the rental-income.