Building Permits in Zillah, WA

A small at-grade accessory slab (walkway, patio pad, or equipment pad) of 200 square feet or less is generally exempt from a building permit under the 2021 IRC (Washington State Residential Code, chapter 51-51 WAC, effective March 15, 2024). A slab that becomes part of a building foundation or supports a future structure falls under a building permit from the City of Zillah Planning & Building Department. Call 811 to locate utilities before digging.

A freestanding deck no more than 30 inches above grade and no more than 200 square feet is exempt from a building permit under the 2021 IRC (Washington State Residential Code, chapter 51-51 WAC, effective March 15, 2024). Anything attached to the dwelling, raised higher, or larger triggers a building permit reviewed by the City of Zillah Planning & Building Department. Zoning setbacks still apply.

A fence 6 feet tall or less is generally exempt from a building permit under the 2021 IRC (Washington State Residential Code, chapter 51-51 WAC, effective March 15, 2024); a taller fence requires a permit from the City of Zillah Planning & Building Department. Local zoning still limits fence height in front yards (often around 3.5 to 4 feet) and on corner lots for visibility.

An at-grade, uncovered concrete or paver patio is exempt from a building permit. Adding a roof, cover, or screen enclosure turns it into an accessory structure that requires a building permit from the City of Zillah Planning & Building Department, and zoning may limit lot coverage.

A retaining wall 4 feet or less measured from the bottom of the footing to the top of the wall, with no surcharge, is exempt from a building permit under the 2021 IRC (Washington State Residential Code, chapter 51-51 WAC, effective March 15, 2024). A taller wall, or any wall supporting a surcharge such as a slope or driveway, requires a permit and engineered design from the City of Zillah Planning & Building Department. Provide drainage behind any wall.