May 17, 2026

RV Storage in Washington State: Rain, Costs & Finding the Right Spot

Washington state has two very different RV storage environments separated by the Cascades. West of the mountains — Seattle, Tacoma, Olympia — you face some of the highest mold risk in the country: 150–180 days of rain per year, persistent cloud cover, and average annual rainfall of 37–55 inches. East of the Cascades — Spokane, the Tri-Cities, Wenatchee — the climate is semi-arid with cold winters and warm dry summers. This guide covers both sides of the state, with costs, facility advice, and the specific prep steps Washington's climate demands.

RV Storage Costs in Washington State (2026)

Western Washington storage costs reflect both the Seattle-area real estate market and high demand driven by the large outdoor recreation community. Facilities often have waitlists for covered and indoor spots, particularly in the Puget Sound region. See how these compare nationally in our state-by-state storage cost guide.

The Mold Problem: Why Western Washington Is Different

The western Washington climate is uniquely hostile to stored RVs because it combines persistent moisture (not just heavy rain, but constant ambient humidity) with moderate temperatures that never get cold enough to inhibit mold growth. Unlike Minnesota, where a frozen winter halts mold activity, Seattle-area winters sit at 40–50°F — the ideal temperature range for mold to grow year-round.

A sealed RV stored outdoors in the Puget Sound region without moisture control will have visible mold inside within one winter season in most cases. This is not an exaggeration — it is the consistent experience of Pacific Northwest RV owners and service centers. Active moisture control is mandatory.

Moisture Control Strategies for Western Washington

• Shore power + electric dehumidifier: The most effective solution. A small dehumidifier (30-pint) running continuously on shore power keeps interior humidity below 50% — the threshold below which mold cannot establish. This is worth paying extra for a facility with electrical hookups. See our guide to storage facilities with shore power.
• Desiccant absorbers: If shore power isn't available, use multiple large desiccant containers (DampRid or equivalent) throughout the RV and replace them monthly October through April. This is a second-best solution — effective but requires regular maintenance visits.
• Roof vents cracked open: Slightly cracked vent fans (with vent covers to block rain) allow air exchange that reduces condensation inside the rig. Fully sealed RVs trap moisture.
• Never use a plastic tarp: Plastic traps moisture underneath and creates exactly the warm, humid, dark environment that mold prefers. Use a breathable cover or no cover at all. See our RV cover guide.

For a comprehensive guide to moisture and mold prevention, see our full article on RV mold prevention during storage.

East of the Cascades: A Different Climate

Eastern Washington is semi-arid, with Spokane averaging only 16 inches of annual rainfall. The storage challenges here are different:

• Cold winters: Spokane sees sub-zero temperatures regularly in January and February. Full winterization is mandatory, including draining all water lines and tanks. See our RV winterization guide.
• Dry summers: UV protection is the summer concern — covered storage recommended for rigs stored during July and August in the Spokane and Tri-Cities area.
• Wind: Eastern Washington is notoriously windy, particularly in the Columbia Basin. A quality cover that ties down securely is important if you store outdoors in this region.

What to Look for in a Washington State Facility

• Shore power (west of Cascades): The single most important amenity for western Washington storage. Without it, mold control is much harder. Prioritize facilities that offer electrical hookups.
• Covered or indoor for western WA: Covered storage significantly reduces the moisture load on your rig. In western Washington, covered storage is recommended for any rig stored more than 3 months.
• Drainage: Western Washington facilities on poorly drained sites can have standing water issues. Look for paved or gravel lots with positive drainage — standing water under your rig increases the moisture and rust risk.
• Year-round access: Washington's outdoor recreation season is year-round for many owners — skiing in winter, hiking in shoulder seasons. 24/7 access is more important here than in states with defined off-seasons.
• Security: Western Washington's urban facilities should have gated access and camera coverage. Petty theft and break-ins at unsecured storage facilities are a documented issue in the region.

Tips to Save on Washington State Storage

• Look 20–30 miles east or south of Seattle — Auburn, Enumclaw, North Bend, and similar communities have significantly lower rates than facilities in Seattle proper
• Annual contracts save 10–15% at most facilities — worth it if you're staying for a full year
• Ask about waitlists for covered spots — getting on a waitlist early is often the only way to get a covered spot in the Seattle metro