Last reviewed October 18, 2026 by Sean McConnell, Team Leader, McConnell Group
The short answer
A floating home is a single-family house on a float, in a legally established moorage with direct sewer and water. It is not a vessel. What people call a houseboat in Seattle is usually a floating on-water residence (FOWR): a vessel or floating structure with detachable utilities, usually in a marina slip. Seattle also recognizes house barges and vessels with dwelling units.
That one difference drives almost everything else: how you finance it, how you insure it, where it can sit and what the monthly bill looks like. Source: RCW 90.58.270, Washington State Legislature
Floating home
SMC 23.60A.202
Floating on-water residence (FOWR)
SMC 23.60A.203
House barge
SMC 23.60A.204
Vessel with a dwelling unit
SMC 23.60A.214
Seattle recognizes these four floating residence types, apart from liveaboards on regular recreational boats. Each verified residence has a unique 3-digit City number it must display. Source: Seattle SDCI: Floating Residences
What is a floating home under Seattle code?
Washington law (RCW 90.58.270) defines a floating home as a single-family dwelling unit constructed on a float, moored, anchored or otherwise secured in waters. It is not a vessel, even though it may be capable of being towed. Seattle covers floating homes in SMC 23.60A.202, and they must sit in legally established floating home moorages.
SDCI Tip 229 adds that floating homes need direct sewer and water connections, must have been legally established or permitted by June 15, 2015, and need an SDCI permit before exterior repair, remodel, expansion or rebuild. Source: SDCI Tip 229
In practice, a floating home looks and lives like a small house. The Houseboats of Seattle FAQ puts the typical one at about 2 bed, 2 bath and 1,100 sq ft, with 200 amp electric and city sewer. Source: Houseboats of Seattle FAQ
What is a floating on-water residence (FOWR)?
A FOWR is a vessel or other floating structure, not a floating home, designed or used primarily as a residence on the water, with detachable utilities. Under RCW 90.58.270 its owner must have held marina space since before July 1, 2014. Seattle lists FOWRs in SMC 23.60A.203. This is what most people here mean by "houseboat".
Typical houseboats are smaller: about 1 bed, 1 bath and 375 sq ft. Most use a 30 amp connection and an onboard blackwater tank that gets pumped out. Most lease marina slips month to month or yearly, with liveaboard permission the marina can take away. Lake Life Seattle counts 215 FOWRs on Lake Union. Source: Houseboats of Seattle FAQ Source: Lake Life Seattle: Floating Home Buying Guide (2026)
What are house barges and vessels with dwelling units?
A house barge (SMC 23.60A.204) is allowed only if it was moored at a Seattle recreational marina before July 1990 and has been used as a residence continuously since, with SDCI verification. A vessel containing a dwelling unit (SMC 23.60A.214) is a craft designed for navigation that has a dwelling unit on board. Both are rare.
Lake Life Seattle counts 27 house barges and 11 vessels with a dwelling unit. Banner Bank's floating home program does not cover barges or liveaboard boats, so financing is limited. Source: Seattle SDCI: Floating Residences Source: Lake Life Seattle: Floating Home Buying Guide (2026)
Comparison table
Here are all four legal types side by side, followed by the two you are most likely to see for sale.
| Floating home | FOWR (houseboat) | House barge | Vessel with a dwelling unit | |
|---|---|---|---|---|
| Code section | SMC 23.60A.202 | SMC 23.60A.203 | SMC 23.60A.204 | SMC 23.60A.214 |
| What it is | Single-family dwelling built on a float, secured in the water. Not a vessel. | Vessel or floating structure used mainly as a residence, with detachable utilities. Marina space held since before July 1, 2014. | Allowed only if moored at a Seattle recreational marina before July 1990 and used as a residence continuously since, with SDCI verification. | A vessel (a craft designed for navigation) that contains a dwelling unit. |
| Utilities | Direct sewer and water connections required. Usually 200 amp. | Detachable. Most use 30 amp and a holding tank. | Varies, ask the marina. | Varies, ask the marina. |
| Where it sits | Legally established floating home moorages (docks) | Marina slips, mostly leased | Seattle recreational marinas | Marinas |
| Can be financed (known lenders) | Yes: Banner, Sound Community Bank, Pacific Crest and others | Limited: Sound Community Bank per Lake Life Seattle | Banner excludes barges. Ask lenders. | Banner excludes liveaboard boats. Ask lenders. |
| Notes | Must have been legally established or permitted by June 15, 2015. SDCI permit for exterior work. | Yellow plaque reads "Floating on Water Residence No." | Lake Life Seattle counts 27. | Lake Life Seattle counts 11. |
Floating Home
SMC 23.60A.202
Legal status
Single-family dwelling on a float. Not a vessel (RCW 90.58.270).
Utilities
200 amp electric and city sewer
Moorage
Mostly owned through a co-op or condo
Typical size
About 2 bed, 2 bath, 1,100 sq ft
2022 median
$1,375,000
Financing
Several portfolio lenders
Can it move?
Rarely. Needs permits and neighbors moved.
Inspection
Home inspector plus dive inspection
Houseboat (FOWR)
SMC 23.60A.203
Legal status
Vessel or floating structure used as a residence, detachable utilities.
Utilities
30 amp connection and a holding tank that gets pumped out
Moorage
Mostly leased marina slips
Typical size
About 1 bed, 1 bath, 375 sq ft
2022 median
$400,000
Financing
Very few lenders
Can it move?
Easier to tow, but liveaboard slips are scarce.
Inspection
Marine survey
What rules apply to every floating residence?
Three big ones. Each verified residence has a unique 3-digit City number it must display, assigned after the 2015 Shoreline Master Program update. Exterior work on a floating home needs an SDCI permit first. And no floating residence may be used as a short-term rental under 30 nights (SMC 23.42.060).
Your dock or marina will have its own rules on top of the City's, so read those documents early. Source: Seattle SDCI: Floating Residences Source: SDCI Tip 229
How to tell which one a listing is
Start with the yellow City plaque on the home. When in doubt, confirm the classification with SDCI.
How the type changes your loan and insurance
The type determines which lenders will consider the loan and which insurance policies apply. Confirm the type before you write an offer.
Read more in the financing guide, the insurance guide and the moorage and dues guide.
FAQ
This is general information, not legal advice. Confirm the classification of any specific residence with SDCI.