Washington Critical areas: what it allows on a lot
Critical areas is Washington law, and the official source is at commerce.wa.gov.
Counties map wetlands, steep slopes and stream buffers under the Growth Management Act; building near them needs a study.
Whether it applies to one lot turns on where the lot is and what it is zoned; the city, county or state office named in the law decides. Mapped areas are approximate. This is a plain reading of public law with its source, not legal advice.
Free, no account. ParcelSheet shows the lot's mapped size, parcel lines and flood zone, and this law on the lot's Washington sheet.
Other Washington laws on a lot: Accessory dwellings (HB 1337, 2023).