Seattle Environmentally Critical Areas: An Early Project Checklist

Steep slopes, potential slide areas, drainage patterns, trees, shorelines, wetlands, and other environmentally critical conditions can change a Seattle home project before the design is settled. They may lead to added Seattle Department of Construction and Inspections (SDCI) review, a pre-application site visit, specialist input, or limits on ground disturbance.

That does not mean a mapped or visible condition automatically prevents a remodel, addition, ADU, DADU, or new home. It means the property and proposed work need to be screened early. An online map, a contractor visit, or this checklist cannot determine feasibility or replace a study that SDCI requires.

The safest first move is simple: gather the address and site facts, define the work and disturbance separately, and confirm the review path before vegetation removal, demolition, grading, excavation, or similar site work begins.

Why site conditions can change the project sequence

A floor plan shows what a homeowner wants to build. It does not, by itself, show how construction may affect a slope, drainage route, tree, shoreline, wetland, or other regulated site feature.

SDCI describes property research, permit-history research, a defined project scope, and site information as early parts of permit preparation. Its [permit-process guidance](https://www.seattle.gov/construction-and-inspections/permits/how-do-you-get-a-permit) also explains that a pre-application site visit may identify issues involving drainage, trees, structures, property lines, ground disturbance, and environmentally critical conditions.

Those findings can affect several early decisions:

where new construction can be placed;
how much soil or vegetation may be disturbed;
which existing conditions must be documented;
whether a qualified specialist may need to study a specific issue;
what information belongs in the site plan or permit submittal; and
whether a seemingly separate task, such as demolition or tree work, should wait.

The practical lesson is not to guess at the final outcome. It is to identify the questions while the scope can still change without undoing finished design work.

A Seattle environmentally critical areas home project checklist

1. Start with the exact property address

Street-level assumptions are not enough. Two nearby lots can have different topography, drainage, tree conditions, past permits, and mapped information.

Record:

the full street address;
the parcel number if available;
known easements or shared access;
past permits, plans, surveys, or studies in the owner's files; and
any earlier correspondence with the City of Seattle.

Past documents are useful context, but they do not establish what SDCI will require for a new proposal.

2. Describe the proposed construction in plain language

Write down what will be added, removed, converted, or rebuilt. Include the intended use of the space and the parts of the existing house that may change.

For example:

remodel an existing lower level without expanding the footprint;
add a rear room and a new exterior stair;
replace a detached garage with a DADU;
build a new home and driveway; or
alter a deck or foundation near a slope.

This is not a permit classification. It is a clear starting scope that SDCI and the project team can evaluate.

3. List site disturbance separately from the building work

Homeowners often focus on the finished structure and overlook the temporary work needed to build it. Make a separate list of possible disturbance:

demolition;
vegetation or tree removal;
grading, excavation, or fill;
foundation and utility trenching;
driveway or access changes;
equipment staging;
drainage work; and
temporary soil storage.

This distinction matters because the building footprint and the disturbance area are not always the same. SDCI states in its [construction-without-a-permit guidance](https://seattle.gov/sdci/codes/common-code-questions/construction-without-a-permit) that work in environmentally critical areas can require permits, and that unpermitted work can result in stop-work orders and penalties.

Do not treat early clearing, demolition, or grading as harmless preparation. Confirm the applicable path first.

4. Record mapped and visible conditions without drawing conclusions

Create a factual list of what is known or observed. Useful notes may include:

a mapped steep-slope or potential-slide-area flag;
a pronounced grade change on or near the lot;
standing water, concentrated runoff, or an existing drainage route;
large trees near the proposed work or access path;
a creek, wet area, shoreline, ravine, or retaining wall;
cracks, settlement, erosion, or past slope repairs; and
structures or improvements close to a property line.

Take dated photos from safe locations. Keep the original files and note where each image was taken. Do not excavate, remove vegetation, enter unsafe terrain, or disturb a feature to collect better evidence.

A map flag is a screening signal, not a site determination. A condition that is not obvious from a map may still matter. The required conclusion belongs with SDCI and any qualified professional the City or project scope calls for.

5. Sketch the relationship between the work and the site

A simple early sketch can make the first conversation more productive. It should show approximate existing structures, the proposed work area, property lines if known, access, major trees, visible slopes, drainage paths, and the likely disturbance area.

Label every dimension or boundary that has not been verified. Do not present an informal sketch as a survey, site plan, or technical analysis.

The purpose is to reveal questions. If the addition, DADU, foundation, utility route, staging area, or access path appears close to a flagged feature, that relationship should be discussed before the layout hardens.

6. Ask SDCI project-specific questions

Bring the address, plain-language scope, disturbance list, photos, and available records. Useful questions include:

Does SDCI identify an environmentally critical area or related review issue for this property?
What property, permit-history, or site information should be gathered next?
Is a pre-application site visit appropriate for the proposed work?
Which activities should not begin before the permit path is confirmed?
Does the proposal call for a particular technical report, plan, or qualified specialist?
Should demolition, tree or vegetation work, grading, excavation, or utility work be included in the early review?
Which assumptions should be resolved before design development continues?

Record the response, date, office or contact, and any referenced project or permit number. If the scope changes, ask whether the earlier guidance still applies.

7. Use specialists for the questions they are qualified to answer

An early contractor conversation can help define construction scope, access, sequencing, and the information needed for design/build coordination. It cannot replace SDCI's property-specific review or the work of a qualified professional.

Depending on the actual condition and City direction, a project may need input from a geotechnical professional, surveyor, arborist, wetland or shoreline specialist, civil or drainage professional, structural engineer, or another qualified discipline. The required role and work product should come from the property, proposal, and applicable review—not from a generic internet checklist.

Do not order every possible study by default. Do not skip a requested study because the site looks manageable. Confirm the question first, then engage the right discipline for that question.

8. Update the design only after the constraints are clearer

Once the next requirements are known, the project team can compare the desired design with the verified site and review constraints. That may affect placement, footprint, access, foundation approach, drainage work, tree protection, construction sequence, or the amount of disturbance.

It may also reveal that the original concept needs more investigation before anyone can responsibly discuss price or schedule. Avoid using an early screening conversation to promise permit approval, study scope, cost, or timing.

What this means for different project types

Interior remodel

An interior-only project may seem unrelated to site conditions. The connection changes if the work also includes foundation repair, exterior excavation, a new opening, utility trenching, drainage changes, demolition, access work, or an expanded footprint. List those elements instead of relying on the word "remodel."

Home addition

An addition introduces a new footprint and usually creates excavation, foundation, access, and drainage questions. Screen the area where old and new construction meet, plus the temporary work zone needed to build it. Love Construction's [home additions service](/services/home-additions/) is relevant once the property facts and desired scope can be discussed together.

ADU or DADU

For a detached unit, include the structure, utility routes, access, staging, and work between the street and building site. A small finished building can still have a larger disturbance area. Homeowners considering this route can review Love Construction's [ADU and DADU construction service](/services/adu-dadu-construction/) while gathering the address and early site information.

New home

New construction can involve broad site planning, demolition, grading, foundations, utilities, drainage, access, and vegetation impacts. That makes early property screening especially important. A concept should remain flexible until the site-specific path is clearer.

A useful first conversation with Love Construction

Love Construction works on Seattle home remodeling, additions, ADUs and DADUs, and new-home construction. The company can discuss the desired construction scope and help organize the design/build questions that need to be resolved. SDCI determines the City review path, and qualified specialists make conclusions within their disciplines.

For a focused first conversation, bring:

the exact address;
a short description of the project;
known permit or property records;
photos of visible site conditions;
a separate list of demolition, vegetation, grading, excavation, drainage, utility, and access work; and
any written guidance already received from SDCI.

Use the [contact form](/#contact) to share those basics. The goal of the first discussion is not a premature yes or no. It is to identify the right next questions before avoidable disturbance or design work begins.