Hiring a waterfront home architect on Lake Washington or Lake Sammamish: what to check before you sign

Choose a waterfront home architect by how they handle four legal questions before any drawing starts. How much of your existing house does the shoreline code let you change? Where does the setback line sit? What does the state exemption cover? What does the dock need? Each answer is a rule in your city’s shoreline master program, and each can decide whether a remodel or a rebuild is the better project. I am David Meade of Piper Cole Architects in Kirkland. I design waterfront remodels and rebuilds and administer construction for the owner. I do not build.

The code figures below were read between 1 and 8 October 2026 from state law and city codes. Confirm any number with your city.

Who this is for

This page is for the owner of a Lake Washington or Lake Sammamish house, or someone about to buy one, with a project budget of $750,000 or more. A typical job is a remodel that opens up the water side of the house, adds a floor or an addition, or replaces a tired house with a new one. Residential remodels at that size are the work I most want. My smallest projects start at a budget of $750,000.

What the shoreline code decides before the first sketch

Under state law the shoreline reaches 200 feet landward from the ordinary high water mark (RCW 90.58.030). That line, the OHWM, is where the water has left its mark on the soil and the vegetation. Everything inside the 200 feet is under your city’s shoreline program, and for many lakefront lots that includes the house.

The owner of a single-family house can build for their own use without a shoreline substantial development permit if the house stays at or under 35 feet above average grade and meets the city’s other requirements, and the garage, deck, driveway and utilities that go with it count too if they sit landward of the OHWM (WAC 173-27-040(2)(g)). The same section adds that an exemption from the permit is not an exemption from the Shoreline Management Act or the local master program. Ecology says the program’s regulations generally apply whether or not a shoreline permit is required.

So the useful question is which rules the program puts on your house: setbacks, vegetation, height, the status of the old house and the dock. In Seattle, initial review of an exemption usually takes 2 to 4 weeks, and the decision must come before your building permit intake. The state rules are in my shoreline exemption guide.

How much of an old waterfront house you may change

Many lake houses were built before today’s setbacks. A legally built house that no longer meets the rules can stay, and every city lets you remodel it, with a limit. The limit is where the architect’s skill shows, because each city measures it a different way.

City	What the code lets you do	Where the limit sits
Mercer Island	A structure within 25 feet of the OHWM may be maintained, repaired, renovated, remodeled and completely replaced if the nonconformance is not increased (MICC 19.13.020).	For other nonconformities, such as a side yard, a house keeps its status only while no more than 40 percent of the length of its exterior walls is structurally altered, counting the previous five years (MICC 19.01.050).
Medina	A nonconforming structure may be enlarged, remodeled or structurally altered if the work does not increase the nonconformity (MMC 16.66.090).	Removing more than 60 percent of the exterior wall framing, measured by length, ends the rights. A house short of the shoreline setback can still be rebuilt in its footprint if the permit application follows within six months.
Kirkland	A nonconforming structure may be maintained, repaired, altered and remodeled if the nonconformity does not grow (KZC 83.550).	Structural alteration of a roof or wall that misses the height or shoreline setback must conform, unless it is repair, window or door work that adds no floor area and costs no more than 50 percent of replacement cost in a year. A detached house built before December 1, 2006 may enlarge its footprint inside the setback by up to 10 percent of its floor area, no further waterward, with restoration.
Seattle	On dry land outside the setbacks, a nonconforming house may be structurally altered, substantially improved or replaced (SMC 23.60A.124).	Inside the setbacks it may be altered but not substantially improved or replaced, except after a casualty. Substantial improvement is work costing 60 percent of market value or more in any five years, or more than 60 percent of the value of the nonconforming portion.
Issaquah, Lake Sammamish	An existing house may be modified or expanded without a shoreline variance if the work is landward of the 35 foot buffer and the 15 foot setback.	If any part of the house is inside the 35 foot buffer and 15 foot building setback zone, the expansion must go landward of both.

Sources: Municode for Mercer Island, Medina and Seattle, read 8 October 2026; the Seattle definition of substantial improvement from the Ecology-hosted program; Kirkland Ordinance 4701, the 2020 text, with no later change found; Issaquah Shoreline Master Program 6.1.3. Confirm with your city.

The same house gets a different answer in a different city. Under each of these tests the part of the house nearest the water is the part you least want to alter, so growth usually goes landward. And work is counted over time: where Mercer Island’s wall test applies, a remodel from four years ago uses up part of today’s allowance.

That leads to the question I price before design starts: keep the house or start over. A rebuild usually has to meet today’s setback. My guides on when a remodel counts as a new house and remodeling a waterfront home show the math, and the city detail is in my Mercer Island, Medina and Kirkland guides.

Where the setback line sits

Setbacks on the same lake can differ by a hundred feet from one city to the next. These are figures I confirm first:

Place	Rule that shapes the house	Code
Mercer Island	Structures set back 25 feet from the OHWM. Hardscape and lot coverage are limited to 10 percent between 0 and 25 feet from the OHWM and 30 percent between 25 and 50 feet.	MICC 19.13.050, Table C
Yarrow Point	Setback 50 feet from the shoreline. Height 25 feet above 1959 ground or 31 feet above finished grade, whichever is less. A nonconforming house may add no more than 25 percent to its structure area or demolish more than 25 percent of its perimeter.	YPMC 17.16.030, 17.16.040, 17.24.040
Hunts Point	The setback depends on the lot’s shoreline environment: A, a stringline between the neighbors’ houses; B, 50 feet from the OHWM; C, 130 feet from the Fairweather Basin centerline; D, set by a map; E, 30 feet.	SMP Table 6.2b
Issaquah, Lake Sammamish	A 35 foot vegetated buffer plus a 15 foot building setback.	SMP 6.1.3

Sources: Mercer Island Municode; YPMC as amended by Ordinance 769 (Town Council packet, June 2025); Hunts Point Shoreline Master Program, October 2015; Issaquah Shoreline Master Program. Read October 2026. Hunts Point calls its Appendix G map approximate, so lot-level lines need the town.

Yarrow Point’s height test is a good example of a rule a generic architect misses. Height counts from the ground as it was in 1959, and the town may require an original grade determination for a new house or a changed envelope. Fill does not raise the limit. Hunts Point’s stringline is another: your neighbors’ houses, not a fixed number, draw your line. The full rules are in my Yarrow Point and Hunts Point guides.

Every one of these lines is measured from the OHWM, so the OHWM needs a surveyor. Kirkland’s code ties Lake Washington’s OHWM to a lake elevation of 18.5 feet on the NAVD 88 datum. Issaquah allows 31.76 feet on the same datum for Lake Sammamish, or a field determination by a qualified biologist. A survey with the OHWM, the setback line and your floor elevations is the first document I ask for.

Additions can trigger shoreline planting. On Mercer Island, new development of 500 square feet or more of floor area, coverage or hardscape, counting the previous five years, requires native vegetation over 50 percent of a 20 foot strip, and 75 percent at 1,000 square feet. Issaquah requires an equal area of buffer enhancement above 500 square feet of new impervious surface. I draw that planting against the sight lines early.

The dock, the bulkhead, high water and floods

The house permit does not cover what sits in the water. A hydraulic project, work that will use, divert, obstruct or change the bed or flow of state waters, needs a Hydraulic Project Approval from the Washington Department of Fish and Wildlife before it starts (RCW 77.55.011, 77.55.021). Docks also have their own shoreline threshold. Ecology lists $28,000 for a freshwater dock that replaces an existing one at equal or lesser size and $13,900 for all other freshwater docks, effective August 5, 2023.

Two cases pull the water into a house project. In Kirkland, a remodel costing more than 50 percent of the house’s replacement cost requires an extra pier or dock, and a covered boat moorage, in the RSA or RMA zone to be removed or brought into conformance. In Issaquah, new residential development must replace existing hard shoreline stabilization with bioengineered stabilization, unless a qualified professional’s assessment is accepted by the city.

Lower floors need their own check. I ask the city whether the lot is in a mapped flood hazard area before I set floor elevations, and I look at drainage and moisture whenever walls are open (moisture management). The view side is in lakefront home design, and Seattle sites are in waterfront home design in Seattle.

What changes the cost and the schedule

I quote a fixed fee for design and permit, set by the project budget and location, about $10,000 to $200,000 depending on scope. You see the number before you commit to drawings. Construction is separate and priced by a builder on finished drawings. These are planning ranges, not bids:

Item	Planning figure	Notes
Whole house renovation	$300 to $550 per sq ft	A 2,500 sq ft house is $750,000 to $1,375,000 (2,500 x 300 and 2,500 x 550).
Addition	$350 to $650 per sq ft	Planning range.
New custom home	$400 to $900 per sq ft	A 2,500 sq ft custom home runs $1.2M to $2.5M all-in.
Demolition of the old house	Typically $20,000 to $50,000	Only if the rebuild wins.
Design to permit submission	Typically 2 to 4 months	Survey, OHWM, existing conditions and the nonconforming analysis come first.
Permit, Seattle	Remodel about 2 to 3 months; new house 6 to 10 months	In Seattle the shoreline exemption comes before the building permit.

Planning ranges from Piper Cole. Cities outside Seattle publish their own review times; I give you a window after I see your scope.

On the water, four things move a project inside those ranges: how much of the old house you keep, whether the dock or bulkhead is in scope, how much planting the addition triggers, and how much survey and soils work the site needs.

What to ask a waterfront architect before you sign

• How much of my house can I change in my city before it counts as new? You want a number or a test, such as wall length or percent of replacement cost, and the code section.
• Where is the OHWM on my lot, and who fixes it? The answer should involve a survey and an elevation.
• Which rooms are inside today’s setback, and what does that allow? This decides remodel or rebuild.
• What does the exemption cover on my project, and what does the shoreline program still require? If the answer is just “you are exempt,” keep asking.
• Will my addition trigger shoreline planting, and where does it go?
• Is the dock or bulkhead in the scope, and who handles the state approval?
• Is the lot in a mapped flood hazard area, and how does that set my floor levels?
• Is your fee fixed, what does it include, and do you build? I do not build, and I quote one fixed fee for design and permit.
• Will you administer construction? That means site visits, answering the builder and checking the work against the drawings.

The process, in order

Step	Time	What you get
Free feasibility check	About a day	A quick read on the lot, the shoreline setback and where the existing house sits against it.
In-depth analysis (optional)	2 to 3 weeks, $1,500	The nonconforming math, with remodel and rebuild options side by side.
Design to permit submission	Typically 2 to 4 months	Design, engineering coordination and the permit set, under the fixed fee.
Shoreline exemption or permit, then building permit	Set by the city and the scope	In Seattle, Yarrow Point and Hunts Point the exemption or permit comes before the building permit. In-water work has its own approvals.
Construction administration	For the length of the build	I visit the site, answer the builder’s questions and check the work against the drawings. I do not build.

Who you would hire

I have been an architect since 1996, an AIA member since 1992 and an NCARB member since 1996. I take on 20 to 30 projects a year. I have won three Masonry Excellence Awards, all for commercial projects, and the Carr residence was featured in Above The Lake and Lux magazines.

Questions

How do I choose a waterfront home architect on Lake Washington?

Ask how they handle the shoreline rules before they draw. A good answer names the test your city uses for an old house, such as wall length on Mercer Island, wall framing removed in Medina or percent of replacement cost in Kirkland, and shows how the ordinary high water mark will be surveyed. Then compare the fee structure, who does the work and whether the architect administers construction.

What does a waterfront home architect do that a regular architect does not?

They design inside a second rulebook. Within 200 feet of the ordinary high water mark, your city’s shoreline master program sets setbacks, vegetation, height and the status of the existing house, and in-water work such as a dock may need state approval. The architect plans around those limits from the first sketch instead of discovering them at permit review.

Does the shoreline exemption mean I can ignore the shoreline rules?

No. The state exemption for an owner’s own single-family house, at or under 35 feet above average grade, covers the shoreline substantial development permit. WAC 173-27-040 says an exemption is not an exemption from the act or the local master program, so setbacks, vegetation and nonconforming rules still apply, and cities such as Seattle issue an exemption decision.

Can I remodel a waterfront house that sits closer to the water than the setback allows?

Usually, if it was legally built, but each city sets a limit. Mercer Island counts structurally altered exterior wall length for some nonconformities (40 percent over five years), Medina counts exterior wall framing removed (more than 60 percent), Kirkland and Seattle use cost tests, and Issaquah sends expansions landward of its buffer. Check the number before you design.

What does a waterfront home architect cost?

I quote a fixed fee for design and permit, set by the project budget and location, about $10,000 to $200,000 depending on scope. The first feasibility check is free and takes about a day. An in-depth analysis is $1,500 and takes 2 to 3 weeks. Construction is separate and priced by a builder. My smallest project budget is $750,000.

How long does a waterfront remodel take to design and permit?

Design to permit submission typically takes 2 to 4 months. In Seattle a remodel permit can be obtained in about 2 to 3 months and a new house takes 6 to 10 months. A shoreline exemption or permit comes before the building permit, and in-water work for a dock or bulkhead has its own approvals, so I give you a window after I see the scope.

Who handles the dock and the state fish and wildlife approval?

The dock is a separate track from the house. Work that changes the bed or flow of state waters needs a Hydraulic Project Approval from the Washington Department of Fish and Wildlife before work starts, and a dock may need its own shoreline permit above a dollar threshold. The dock itself is built by a marine contractor. Piper Cole does not build.

What should I send for a free feasibility check?

Send the address, whether you own the house or are buying it, and what you want to change. A survey, if you have one, helps. In about a day I tell you how the shoreline setback and your city’s rules read against the house, and whether the $1,500 in-depth analysis is worth doing next.