ADU Rental Rules in Redmond: A 2026 Owner's Guide
Redmond allows two ADUs per lot, up to 1,000 square feet, with no owner occupancy rule. The ADU rental rules Redmond owners need, from city code to rent cap.
Redmond, Washington is one of the friendlier Eastside cities for renting out an accessory dwelling unit. Under the Redmond Zoning Code, RZC 21.04.1110, every residential lot may have two ADUs or tiny homes. An ADU can be attached to the main house or built as a detached backyard cottage, its size is capped at 1,000 square feet, and there is no owner occupancy requirement. That means you can live in the main house and rent the ADU, rent both, or rent the ADU while the main house sits between uses. One important caveat: Redmond updated its ADU ordinance in mid-2026, through Ordinance 3261 adopted June 2, 2026 and still pending codification, so owners should confirm current requirements with the city's planning department before building or converting.
The short version: Redmond allows two ADUs or tiny homes per residential lot, attached or detached, with a maximum size of 1,000 square feet and no requirement that the owner live on the property. Long term rental of an ADU is allowed. Once a tenant moves in, Washington State's Residential Landlord-Tenant Act, RCW 59.18, and Redmond's local tenant protections in RMC 9.54 apply to the ADU tenancy in full.
What Does Redmond Allow You to Build and Rent?
The ADU rules live in the Redmond Zoning Code at RZC 21.04.1110. As of August 2026, the operative provisions for an owner are:
- Two ADUs or tiny homes per residential lot. The unit can be added inside the primary home, attached to it, or built as a detached structure on the same lot.
- Maximum ADU size of 1,000 square feet. The city's Administrator can approve a larger unit in narrow cases, such as an ADU occupying an entire floor of the main house. A tiny home is capped at 400 square feet.
- No owner occupancy requirement. Nothing in the section requires you to live in the main house, or on the lot at all, to rent an ADU long term.
- Normal residential standards apply. A detached ADU must meet the lot coverage and other standards of its zone, and the unit must meet health and safety codes.
About that mid-2026 update: Ordinance 3261 amended RZC 21.04.1110 as part of a larger zoning package aligning Redmond with Washington State housing law. The ordinance text keeps the two-unit allowance, the 1,000 square foot cap, and attached or detached siting unchanged, but the amendment has not yet been folded into the published code. Before you commit money to a build or conversion, confirm the current requirements with Redmond's planning department.
Why Are ADUs Growing Across Washington State?
Redmond's rules did not appear in a vacuum. Washington State's 2023 ADU law, House Bill 1337, now codified at RCW 36.70A.680 and RCW 36.70A.681, set a statewide floor for cities inside urban growth areas. Cities must allow at least two ADUs per lot where single-family homes are allowed, must permit detached units, may not require the owner to live on the property, and may not cap ADU size below 1,000 square feet.
That framework is why ADU rules now look similar across the Eastside. Kirkland runs a comparable program, which we covered in our guide to ADU and DADU rentals in Kirkland, and Redmond's standards sit right at the state floor: two units, 1,000 square feet, no owner occupancy condition.
For owners, the practical effect is more usable lot, more housing, and a legal way to add rental income that can help with the mortgage. The state law expressly leaves one lever with cities, though: they may still restrict using ADUs as short term rentals, and Redmond does regulate that, as covered below.
What Rules Apply When You Rent Out Your ADU Long Term?
An ADU tenancy is a full tenancy. The Residential Landlord-Tenant Act applies to the ADU exactly as it would to a house, which means the ADU needs its own written lease, its own deposit accounting, and its own notices. On top of the state layer, Redmond adds its local tenant protections chapter, RMC 9.54, in effect since 2022:
- Move-in costs are capped. Under RMC 9.54.040, move-in fees plus the security deposit cannot exceed one month's rent combined, and tenants can elect to pay in installments.
- Late fees are capped at 1.5 percent of monthly rent under RMC 9.54.050.
- Rent increases need long notice. Under RMC 9.54.030, an increase over 3 percent requires 120 days' written notice and an increase over 10 percent requires 180 days, both longer than the state's 90-day minimum in RCW 59.18.140.
- Deposits come back on a clock. Washington State law, RCW 59.18.280, gives you 30 days after move-out to return the deposit with a documented statement for anything withheld.
- Entry requires notice. RCW 59.18.150 requires at least two days' written notice to enter an occupied unit, or one day to show it to a prospective tenant or buyer.
If you are setting up your first rental in the city, our guide to renting out your home in Redmond walks through the whole compliance stack in detail.
How Do You Manage a Main House and an ADU as Two Rentals?
Renting both the main house and the ADU puts two separate tenancies on one lot, and that is where most self-managing owners get into trouble. The mechanics matter:
- Screen both tenancies with the same written criteria. Different standards for the front house and the back cottage is exactly the kind of inconsistency that creates Fair Housing exposure. One set of criteria, applied identically to every applicant.
- Decide utilities up front. Many ADUs share meters with the main house. If the units are not separately metered, the lease needs a clear written allocation method for water, sewer, power, and garbage, so neither resident is guessing at their share.
- Put the shared spaces in the lease. Yard use, parking assignments, and any shared laundry or storage should be spelled out per unit, in writing, not left to the neighbors to negotiate.
- Respect the privacy line. Each unit gets its own entry notices, its own communications, and its own quiet enjoyment. Treat the lot as two addresses, because legally it now functions that way.
The takeaway: one lot, two tenancies, two complete sets of paperwork. The shared-lot details you settle in the lease are the ones that never turn into disputes later.
Can You Rent a Redmond ADU Short Term?
Only with a city business license. Under RMC 5.04.130, long term rentals of four or fewer units at one location are exempt from Redmond's business license requirement, but any short term rental requires a license, regardless of size, and Redmond tightened its short term rental rules effective January 1, 2026. State law backs the city up here: RCW 36.70A.680 expressly allows cities to restrict the use of ADUs as short term rentals.
Our focus at Sagareus Property Management is long term tenancy, which is also where the ADU math tends to be steadiest: continuous occupancy, one set of rules, and none of the licensing overhead.
Does the State Rent Cap Apply to Your ADU?
Usually, with a notable exemption. Washington State's 2025 rent stabilization law, RCW 59.18.700, limits rent increases for covered tenancies to 7 percent plus inflation or 10 percent, whichever is less, and bars any increase during the first 12 months of a tenancy. The Washington State Department of Commerce publishes the exact ceiling each year; for 2026 it is 9.683 percent.
The nuance for ADU owners sits in the exemptions at RCW 59.18.710. A tenancy in a single-family owner-occupied residence, where the owner rents out no more than two units or bedrooms, expressly including an attached or detached ADU, is exempt from the cap. Live in the main house and rent the ADU, and the cap generally does not limit your increase. Two things narrow that exemption: it does not apply when the owner is a corporation, a REIT, or an LLC with a corporate member, and it disappears if you move out and rent both units. A separate exemption covers units whose first certificate of occupancy is 12 or fewer years old, which can reach a newly built ADU. Exempt or not, every increase still needs proper written notice, including Redmond's 120 and 180 day tiers. This is information, not legal advice; how the exemptions apply to your ownership structure is worth confirming before you rely on one.
Common Questions About ADU Rentals in Redmond
How Many ADUs Can I Have on My Redmond Lot?
Two. Under RZC 21.04.1110, two ADUs or tiny homes are allowed on each residential lot in Redmond, Washington, attached to the primary home or detached, with each ADU capped at 1,000 square feet. Redmond amended the ordinance in mid-2026, so confirm current requirements with the city's planning department before building.
Do I Have to Live On the Property to Rent Out My Redmond ADU?
No. Redmond has no owner occupancy requirement for long term ADU rentals, consistent with Washington State law, RCW 36.70A.681, which bars cities from imposing one. Note that where you live still affects the state rent cap: the owner-occupied exemption in RCW 59.18.710 only applies while you live on the property.
Do I Need a Business License to Rent Out an ADU in Redmond?
Not for a long term rental; RMC 5.04.130 exempts long term rentals of four or fewer units at one location. Any short term rental requires a Redmond business license regardless of size, under rules the city tightened effective January 1, 2026.
How Sagareus Handles Leasing and Marketing
A vacant home is won or lost on speed and presentation, so we treat both as disciplines, not hopes. Every day a unit sits empty is income the owner never gets back, and the listing that responds first and looks best is the one that fills. Here is how we run it:
- Respond to every lead fast, within minutes. The first responder usually wins the showing, so inquiries get a real answer right away, not whenever someone gets to them. Every showing is scheduled and accompanied by our team.
- Professional photos and a standards-based listing, no exceptions. Real photography, an accurate description, and complete amenities. We do not cut this corner, because a weak listing quietly costs weeks of vacancy.
- Price to the market, then adjust on activity, not ego. We set the opening rent from current comparable rentals and your priorities, then watch inquiries and showings against pre-planned checkpoints and move when the data says to.
You set the goal, whether that leans toward top rent or fastest occupancy. We bring the market read, run the system, and report the numbers every week until the lease is signed.
Speed and presentation are not luck. They are how we shorten your vacancy.
An ADU is a small unit with a full-size compliance stack, and leasing it well is the same discipline as leasing a house. Sagareus Property Management manages main-house-plus-ADU properties across the Eastside, including full Redmond property management. Curious what professional management would cost for your ADU or your whole property? Our instant calculator gives you a real range in under a minute, no email required. Request your instant estimate.