Washington Mobile Home Park Rent Control: 2026 Guide

Is mobile home lot rent controlled in Washington?

Yes. As of May 7, 2025, Washington caps how much you can raise lot rent in a manufactured or mobile home community. House Bill 1217 (Laws of 2025, ch. 209) created a statewide rent-stabilization system, and it gave manufactured-home communities their own, stricter rule than ordinary apartments.

For your lots, the ceiling is a flat 5% per 12-month period, and you cannot raise rent at all during a resident's first 12 months. This is codified in the Manufactured/Mobile Home Landlord-Tenant Act at RCW 59.20.370. This is not local ordinance you can shop around — it applies everywhere in the state.

Because the number is lower than the general-residential cap and the penalties run through the Attorney General, treat every lot-rent increase as a compliance step, not a routine one.

The 2025 HB 1217 cap: flat 5%, effective May 7, 2025

RCW 59.20.370(1) is the operative language: a landlord may not increase rent '(a) During the first 12 months after the tenancy begins; and (b) During any 12-month period of the tenancy, in an amount greater than five percent.'

Note what that 5% is and is not. General apartments and houses are capped at 7% plus CPI, or 10%, whichever is less. Manufactured-home LOTS get a separate, lower, FLAT 5% — there is no CPI add-on and no 10% alternative for your spaces. Do not apply the 7%+CPI math to a lot rent.

The law took effect immediately when Governor Ferguson signed it on May 7, 2025. The Attorney General's guidance confirms it plainly: 'the maximum annual percentage rent increase allowed is 5%,' and 'the park owner may not raise your rent, in any amount, during the first 12 months.' Any increase noticed on or after that date must fit inside 5%.

You must give 90 days' (three months') written notice

Even a compliant 5% increase is only valid if you notice it correctly. RCW 59.20.090(2) requires that a landlord 'shall notify the tenant in writing three months prior to the effective date of any increase in rent' — that is 90 days, longer than the general-residential rule and much longer than the old 60-day standard.

RCW 59.20.370(2) ties the cap and the notice together and requires service consistent with the Manufactured/Mobile Home Act (RCW 59.20.390, 59.20.090(2)) and RCW 59.12.040. In practice: put the increase in writing, keep it at or under 5%, and deliver it at least three full months before the new rent starts.

A late or defective notice can invalidate the increase regardless of the percentage, so calendar the three-month lead time and document delivery.

Exemptions are narrow — and the statewide cap replaces local control

Do not assume HB 1217's well-known residential exemptions apply to your park. The 12-year 'new construction' exemption lives on the apartment/house side (RCW 59.18) and does not open up ordinary lot rents. The exemptions that actually reach manufactured-home communities are the short list in RCW 59.20.380.

Those cover roughly: lots owned by a public housing authority, public development authority, or nonprofit where rents are already regulated by other law; the first 12 months after a qualifying sale of the community to an eligible organization (to help cover the purchase cost); and a one-time market-rate reset when a lot turns over because the prior resident sold their home. If none of these fit, the flat 5% cap governs.

On local control: RCW 35.21.830 still preempts cities and counties from setting their own rent caps, and HB 1217 did not repeal that. So there is no patchwork of local park-rent ordinances to track — the state's 5% cap is the single operative control.

Rent-increase rules at a glance in Washington

• Lot-rent cap
  Flat 5% maximum in any 12-month period for manufactured/mobile home lots (RCW 59.20.370(1)(b)) — no CPI add-on, unlike the 7%+CPI/10% general-residential cap.
• First-year freeze
  No increase of any amount during the first 12 months of a tenancy (RCW 59.20.370(1)(a)).
• Notice period
  90 days / three months' written notice before the increase takes effect (RCW 59.20.090(2)); serve per RCW 59.12.040.
• Effective date
  May 7, 2025 (HB 1217; Laws of 2025, ch. 209), effective immediately on signing.
• Exemptions
  Limited to RCW 59.20.380 (public/nonprofit-regulated communities, first 12 months after a qualified community sale, one-time increase on lot turnover). The residential new-construction carve-out does not free up ordinary lot rents.
• Local control
  Local rent control remains preempted (RCW 35.21.830); the statewide 5% cap is the operative limit.
• Enforcement
  The Washington Attorney General enforces HB 1217; over-cap increases expose you to complaints, penalties, and tenant remedies.

Operator best practices in Washington

• Cap every increase at 5%
  Set your annual lot-rent bump at 5% or less and never apply the 7%+CPI apartment formula to a manufactured-home space.
• Honor the first-year freeze
  Do not schedule any increase inside a resident's first 12 months — build that into your lease-anniversary calendar.
• Send notice 90 days out
  Issue written increase notices at least three full months before the effective date and keep proof of service per RCW 59.12.040.
• Verify before relying on an exemption
  Only the RCW 59.20.380 exemptions reach lots; confirm your specific situation in the statute before exceeding 5%, and document why it qualifies.
• Don't wait on local rules
  There are no valid local park-rent ordinances to follow (RCW 35.21.830 preempts them); comply with the state cap everywhere you operate.
• Keep clean records
  Log each rent history, notice date, and percentage so you can show AG-ready compliance if a resident complains.
• Build a relationship with a Washington MHP attorney
  Retain counsel who specializes in the Manufactured/Mobile Home Landlord-Tenant Act to review your notice templates and any exemption claims before you rely on them.