Clyde Hill residential zoning
How big a home can you build in Clyde Hill?
For a new house in Clyde Hill, start with three numbers: 30% structural coverage, 60% impervious coverage, and 25 feet of height above original grade. Then check where the house can sit. The R-1 rules do not set a general floor-area ratio (FAR), but that does not mean you can build any size home you want.
On this page14 sections
Official starting point: Clyde Hill R-1 rules (Chapter 17.16). Verify the parcel zone, current code, and every applicable footnote before fixing the design.
The main rules for a new house
These are the R-1 starting rules for a principal home, not a complete permit checklist. ADUs and other housing types can have different provisions.
| Rule | Starting limit | What it controls |
|---|---|---|
| Structural coverage | 30% of the building site | The area occupied by counted buildings and structures |
| Impervious coverage | 60% of the building site | Counted structures plus driveways, patios, and other runoff-producing surfaces |
| FAR / total floor area | No general R-1 FAR limit stated | Do not turn a coverage percentage into a legal living-area allowance |
| Main-house height | 25 ft above original grade at every point | The roof and building must fit within the point-by-point height limit |
| Front setback | 30 ft | Measured from the applicable street/right-of-way or access boundary |
| Rear setback | 35 ft | Limited exceptions apply to small accessory structures |
| Standard minimum building site | 20,000 sq ft; 100 ft frontage and depth | Existing smaller legal lots need a separate nonconforming-lot check |
Side setbacks depend on lot size
| Lot area | Required side yards |
|---|---|
| 15,000 sq ft or more | 15 ft on each side |
| More than 10,000 but less than 15,000 sq ft | 10 ft on each side, with an additional upper-building angle rule |
| 10,000 sq ft or less | 15 ft combined, at least 5 ft on either side, with the upper-building angle rule |
Example: coverage on a 20,000-square-foot lot
Assume the City accepts 20,000 square feet as the building-site area used for both calculations. These are example design quantities, not a permit determination.
| Calculation | Square feet | Share of the lot |
|---|---|---|
| Maximum structural coverage: 20,000 × 30% | 6,000 | 30% |
| Proposed house and garage (4,000) + other counted structures (500) | 4,500 | 22.5% |
| Structural coverage left: 6,000 − 4,500 | 1,500 | 7.5% |
| Maximum impervious coverage: 20,000 × 60% | 12,000 | 60% |
| Proposed structures (4,500) + separate counted hardscape (3,500) | 8,000 | 40% |
| Impervious coverage left: 12,000 − 8,000 | 4,000 | 20% |
Coverage is not the same as living space
Structural coverage measures how much of the site is occupied by counted structures, not the sum of their floors. A second floor above the same footprint generally adds floor area without doubling coverage. An attached or detached garage still uses coverage even though it is not living space.
FAR would divide the code-counted floor area by lot area. Clyde Hill's R-1 chapter does not state a general FAR cap. You should not borrow a neighboring city's FAR or call 30% coverage a 30% living-area limit. Nor does doubling the footprint prove that two full floors will fit under Clyde Hill's height rules.
Ask your architect for separate totals for living space, garage and other floor area, structural coverage, and impervious coverage. A listing's square footage cannot substitute for those plan calculations.
Setbacks tell you where the house can go
A setback is measured to the eave or outermost building projection, not simply the exterior wall. Along a street or access route, the relevant line may be a right-of-way boundary or the nearest edge of an access easement, private road, or alley, not the curb or a fence.
Imagine a simple 100-by-200-foot interior lot with 15-foot side yards, a 30-foot front yard, and a 35-foot rear yard. The starting setback rectangle is 70 by 135 feet, or 9,450 square feet. But the 30% structural limit still allows only 6,000 square feet of counted structures. Fitting inside the setback rectangle does not let you fill it.
On lots under 15,000 square feet, the side-yard code also limits the upper portion of the building with an angled line beginning 12 feet above grade at the required setback and rising away from the side boundary. Have your architect draw the City's required 30-degree rule in section; do not assume a second floor can occupy the entire first-floor footprint.
The simple rectangle above is not a corner-lot formula. Identify every yard before calculating the space left for a house.
Corner lots: two front yards and no ordinary rear yard
Clyde Hill generally requires a 30-foot front setback along each street on a corner lot. The other yards are side yards, so the main house does not also need the ordinary 35-foot rear setback. SR 520 and 84th Avenue NE are exceptions to the street-front rule. One side is treated as rear only for the separate accessory-building placement provisions.
For a corner lot larger than 10,000 but smaller than 15,000 square feet, the starting distances are therefore 30 feet along each qualifying street and 10 feet along each interior side. At 15,000 square feet or more, those side distances become 15 feet each. The smaller-lot upper-building angle restriction still applies, so these ground-level distances do not define the whole second floor.
Through lots and private-road lots require their own yard determination. Confirm the survey, street boundaries, and City interpretation before relying on a four-number setback summary.
The 25-foot height limit follows historic ground levels
Original grade is the land's topography when Clyde Hill incorporated in March 1953, not necessarily today's lawn or the ground beside an existing house. The City determines it from the available evidence. Adding fill or excavating a basement does not reset that reference.
This matters for tall ceilings, roof pitch, a daylight basement, and a second floor on a slope. Get the City's original-grade record before settling on the floor plan. A house that works on a flat lot may need a stepped design on a hillside.
A shed exception is not a garage or ADU allowance
The R-1 rear-yard rule allows a qualifying small accessory structure at least 10 feet from lot lines, no more than 12 feet tall, and no more than 220 square feet of projected roof area. Garages and carports are not allowed under that rear-setback exception.
The accessory-structure rules generally allow no more than three such structures, no more than 220 square feet each, and no more than 340 square feet combined. An attached accessory structure is not automatically outside those rules. ADUs have separate provisions; do not design a DADU using the shed exception.
What to ask for before you commit to a design
Ask for one site plan showing the surveyed boundaries, the building-site area used in each calculation, required yards, roof projections, existing and proposed structures, hard surfaces, access, easements, trees, and drainage. Pair it with building sections showing original grade and roof heights.
Then test the spaces that matter to you: the garage, a usable backyard, an outdoor kitchen or pool, guest parking, and the view from the main living rooms. The maximum house on paper is not always the best house to live in, or the least expensive one to build.
Other rules to check
Other rules that can change the answer
These items link to the city rules behind the guide. They are useful starting points, but they do not replace a property-specific review or a search for private covenants and easements.
| Topic | What it means | Official source |
|---|---|---|
| FAR | The R-1 district has no stated base FAR. Structural coverage, impervious coverage, setbacks, height, and lot geometry control the initial envelope. | CHMC 17.16 ↗ |
| Setbacks | Front 30 ft and rear 35 ft. Side yards are 15 ft each at 15,000 sq ft or more; 10 ft each above 10,000 and below 15,000; and 15 ft combined with a 5-ft minimum at 10,000 sq ft or less. Smaller lots also have an upper-story angle plane. | CHMC 17.16.040–.060 ↗ |
| Lot coverage | Maximum structural coverage is 30%. It is a footprint control, not a total-floor-area limit. | CHMC 17.16.080 ↗ |
| Impervious surface | Maximum impervious coverage is 60%, subject to a surveyed site and drainage calculation. | CHMC 17.16.080 ↗ |
| Height | Maximum height is 25 ft above original grade at every point of the building, with limited exceptions. | CHMC 17.16.020 ↗ |
| Trees | The reviewed R-1 code does not state a citywide development tree-retention percentage. Chapter 17.38 instead governs certain private-tree view and sunlight disputes. | CHMC Chapter 17.38 ↗ |
| Existing private views | Chapter 17.38 applies when growth of a private tree unreasonably obstructs a qualifying existing view or sunlight. It does not create a right to a totally unobstructed view and is not a veto over a code-compliant building. | CHMC Chapter 17.38 ↗ |
| Wetlands, slopes, and critical areas | Clyde Hill's 30 percent structural-coverage number is only a base zoning screen. Critical areas and buffers can prevent construction in part of a lot, and the current code also restricts middle housing and ADUs on or within mapped critical-area conditions. Use the City's current critical-area information and a field-based wetland or geotechnical review before relying on the R-1 setback or coverage diagram. County mapping is preliminary, and the actual feature, buffer, and safe building area must be confirmed for the property. | Clyde Hill R-1 code ↗ |
Practical worksheet
Put this guide to work
Worksheet updated . This is a planning example. Regulatory sources and data have their own dates.
Use three separate drawings and calculations
Illustration only: a 10,000-square-foot qualifying lot with a 0.50 FAR would permit 5,000 square feet of counted floor area. A hypothetical 35% building-coverage cap would allow a 3,500-square-foot footprint. Those are different ceilings, not two allowances to add together. This example does not assign either ratio to your city or parcel.
- Floor-area schedule
- List each level, garage, ADU, basement and other space. Cite the local inclusion or exclusion rule beside any area you do not count.
- Coverage and surface schedule
- Calculate the footprint separately from all regulated hard or impervious surfaces. Include existing retained improvements and use the correct eligible lot area for each ratio.
- Usable site plan
- Place the building inside the actual yards, easements, critical areas, tree protections and access requirements. Show room for construction as well as the finished building.
A house can pass FAR and fail coverage. It can pass both and still have no workable driveway or excavation area. Review the three documents together. Pervious paving, basements and garages do not receive the same treatment in every jurisdiction.
Property-specific checks
What can change the table
- The minimum-lot-size rule excludes private-road and pipe-stem areas. Have the City confirm the building-site area used for your coverage calculations rather than using a listing's lot size without checking.
- An existing smaller lot or older nonconforming house needs an individual review. Demolition does not automatically preserve every old setback or building size.
- Easements, critical areas, drainage, recorded covenants, and permit conditions can further limit construction.
- This guide covers a new principal home. Confirm separate ADU, cottage-housing, and other use-specific rules for a different project.
How to use this guide
How to use the zoning table for a real property
- 1
Find the parcel on the city's current zoning map and copy the complete zone name.
- 2
Read the full row, table footnotes, and definitions. Do not use only the front setback.
- 3
Check corner-lot yards, access easements, critical areas, shorelines, trees, overlays, and recorded restrictions.
- 4
Use a boundary and topographic survey to place the setbacks against the actual lot.
- 5
Have the city or project team confirm any uncertainty before the design is fixed.
Official resources