Cottage Lake (WA): Motor and Boating Rules
King County · near Woodinville · managed by King County
- Gas outboard NO
- Electric trolling YES
- PWC / jet ski NO
- King County, WA
- King County
Quick answer
Leave the gas outboard at home for Cottage Lake. Electric motors are the only propulsion allowed besides paddle and oar. Cottage Lake in WA is restricted to electric motors only — gasoline engines are prohibited under King County regulations (verified July 26, 2026). Size the motor to your hull, and check the notes below for any lake-specific conditions. Rules change and local ordinances may add restrictions — always confirm with King County before you launch.
Rules at a glance
What this means in practice
Battery math decides your day on Cottage Lake. Divide the battery's amp-hours by your motor's draw: a 100 Ah battery on a motor pulling 25 A at half speed gives about four hours continuous — more with intermittent use, less in wind and cold water. A second battery or a paddle backup is cheap insurance.
Electric-only waters in Washington tend to be managed fishing lakes, and it shows: no wake chop, no fuel sheen, and quiet banks. If you fish from a kayak, a bow- or transom-mount conversion makes you a legal motorboat here — registration rules for motorized craft then apply, so check your paperwork before launch.
Worth knowing about Cottage Lake: King County Code 12.44.340 makes it unlawful to use or operate any internal combustion engines on Cottage Lake, with county-posted signage required. K.C.C. 12.44.070 separately limits motor-powered watercraft on King County lakes to 8 miles per hour..
Planning options around Washington? The neighboring pages in our database cover Battle Ground Lake (Electric only, Clark County) and Deep Lake (No wake, Thurston County), and the state hub lists all verified Washington lake motor rules with the official source behind each.
Common mistakes on Electric only water
Leaving the gas outboard mounted "just in case." Depending on the agency, an attached combustion engine can be a violation even when it stays off. Confirm with King County or leave it home.
Undersizing the battery. Wind is the tax on electric water — a battery that lasts four calm hours lasts two windy ones. Bring reserve capacity or a paddle backup.
Before you launch — verify
- The live rulebook is here: King County
- For edge cases — mounted-but-unused motors, tournaments, temporary orders — phone the King County office covering King County.
- Our most recent source check for this page: .
Rules change and local ordinances may add restrictions — always confirm with King County before you launch.
Frequently asked questions
Are gas motors allowed on Cottage Lake?
No — Cottage Lake is electric-only. Combustion engines of any size are banned; trolling motors are the legal alternative. Verified July 26, 2026.
Can I use an electric trolling motor on Cottage Lake?
You can. Electric propulsion is permitted on Cottage Lake; most boats here run a 12 V transom-mount trolling motor. Pack a paddle as backup for when the battery fades.
Are jet skis (PWC) allowed on Cottage Lake?
Jet skis are out on Cottage Lake. The lake's motor rule leaves no room for personal watercraft.
Who enforces boating rules on Cottage Lake?
King County (county government) sets and enforces the motor rules on Cottage Lake, with possible additional ordinances from King County or local municipalities. State boating officers and local law enforcement both patrol restricted waters.
Where do I verify the current rules for Cottage Lake?
Use the official document linked in the Sources section of this page — it is what this summary is based on — or go to King County directly. We last verified this page against the source on July 26, 2026.