Bolthole Index

Yakima County, Washington

Building permits, zoning and septic rules in Union Gap, Washington

For building permits in Union Gap, Washington, start with the city’s Community Development Department; the work proposed determines whether a building permit is needed.1 Union Gap sets zoning inside city limits, while Yakima Health District administers septic requirements.23 In Yakima County’s Union Gap, septic tanks are generally prohibited except as the city sewer chapter allows, so confirm sewer service before planning an off-grid home.4

At a glance

Building permits
City Community Development; confirm requirements for the proposed work1
Zoning
City zoning districts and permitted-use table apply2
Septic
Yakima Health District reviews systems where city sewer rules allow them34
Owner-builder
City declaration required; contractor-registration exemption does not waive building approvals56
Tiny homes
State building-code compliance and local installation and location approvals apply7
Manufactured homes
Class A, B and C homes permitted within manufactured-home parks; ask City Planning about other sites8
Building permit fees
Vary with valuation, construction type and use9

Who to call

Building permits

City of Union Gap Community Development — Building

City building permit applications, plan review and inspections

509-575-3638

102 W. Ahtanum Road Union Gap, Washington 98903

Planning & zoning

City of Union Gap Community Development — Planning

City zoning, land-use review and floodplain information

509-575-3638

Septic permits

Yakima Health District Environmental Health — On-Site Sewage

Septic permitting, review and inspections throughout Yakima County

509-249-6508

[email protected]

1210 Ahtanum Ridge Drive, Union Gap, WA 98903

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

Going off-grid in Union Gap means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Union Gap, WA?

Union Gap’s Community Development Department asks anyone proposing building work inside city limits to contact the city because building permit requirements depend on the work.1 Union Gap follows the building, mechanical, plumbing and energy codes adopted and amended by Washington State.10 New structures and extensive remodels require detailed plans prepared by qualified engineers or architects; smaller projects such as patio covers, carports and decks can use simpler plans prepared by owners or contractors.1 An owner acting as the contractor must complete the city declaration, and the contractor-registration exemption does not remove applicable building permit or inspection requirements.56

Who issues building permits in Union Gap, and how do you apply?

For building permit questions inside Union Gap, call Community Development at 509-575-3638.1 Building, plumbing, mechanical and fire-code permits use the city’s General Application for Construction.1 Residential applications require 2 sets of plans, 1 site plan, energy compliance forms and engineering documentation.1 The city limits emailed applications to signs, stand-alone mechanical or plumbing work, fences, roofs and demolition; applications over 5 pages must be mailed.1 Union Gap building permit fees depend on valuation, construction type and use, so request an estimate for the actual project rather than treating a building permit as a flat-fee purchase.9

Does Union Gap have zoning, lot-size and setback rules?

Union Gap has city zoning districts and a permitted-land-use table; a blank entry in that table means the use is not permitted in that district.2 City Planning explains that parcel zoning determines which uses, building locations and development activities require land-use approval, and encourages a pre-application meeting.11 Ask City Planning for the parcel’s district and the applicable lot-size, setback, coverage and height standards before choosing a house footprint.11 We could not confirm those residential dimensional standards or a city minimum dwelling size; ask City Planning with the address or parcel number ready.11 Union Gap permits Class A, B and C manufactured homes within manufactured-home parks; ask City Planning about a manufactured home on an individual lot.811

How do septic permits work inside Union Gap?

Union Gap generally prohibits constructing or maintaining septic tanks and other listed private sewage facilities except as its sewer chapter provides; city sewer availability must therefore be resolved before assuming septic is an option.4 Yakima Health District administers on-site sewage requirements inside Union Gap.3 Where a new septic system is allowed, the Health District requires a site and soil evaluation, design, application and fee, then issues a septic system permit after design approval.12 The Health District inspects a new system before it is covered.13 For septic alterations and repairs, the installer and designer prepare an as-built record, and the Health District schedules its final inspection after submission.14

Can you live in an RV or tiny home in Union Gap?

We could not confirm permission for living in an RV on private land in Union Gap; ask City Planning to review the parcel and proposed duration before relying on an RV during construction.11 Union Gap’s public-area camping prohibition concerns public areas and does not establish a general private-property camping rule.15 Washington’s tiny-house rules require state building-code compliance and local approvals for foundation, installation and location; a wheeled structure may instead be classified as an RV or park model.7 We could not confirm a Union Gap tiny-home occupancy provision, so ask City Planning about the proposed structure and use, then ask Building about the construction approvals.111

Building a home in Union Gap: what are the steps?

  1. Bring the address or parcel number to Union Gap City Planning and request zoning and floodplain information and a pre-application meeting.11
  2. Resolve sewer availability before selecting septic; if septic is allowed, obtain Yakima Health District’s site evaluation and septic system permit approval.412
  3. Prepare the city construction application, plans, site plan, energy forms and engineering documents, and request a project-specific building permit fee estimate.19
  4. Coordinate required inspections with City Building, giving the permit number, site address, inspection type and contact information; for a new septic system, arrange the Health District’s final inspection before covering it.113

What should you check before buying land in Union Gap?

Ask Union Gap City Planning for floodplain and FEMA information with the parcel number or address ready.11 Washington floodplain development requires a local-government floodplain development permit, and local standards may extend beyond the mapped FEMA floodplain.16 Ask Community Development to review access: Union Gap’s discretionary land-use review can control driveway access points, while county-road approaches and state-highway access have separate requirements for those rights-of-way.171819 We could not confirm city-specific private-well requirements; Washington’s groundwater permit exemption remains subject to local requirements and senior water rights.20 For land outside city limits, use the Yakima County guide for the county’s unincorporated-area zoning answer.21

Watch-outs

  • Do not assume sewer-free living is available in Union Gap: the city’s prohibition on private sewage facilities has only the exceptions provided in its sewer chapter.4
  • Yakima County’s temporary RV occupancy rule applies in the county’s land-use jurisdiction; ask Union Gap City Planning about RV occupancy inside city limits.2211
  • We could not confirm a general Union Gap certificate-of-occupancy requirement; ask City Building which approvals are needed before moving in.1

Sources

  1. City of Union Gap Community Development — Building (uniongapwa.gov)
  2. Union Gap Municipal Code 17.04.030, Table of permitted land uses (Union Gap), quoted and re-checked
  3. Environmental Health Program (Union Gap), quoted and re-checked
  4. Union Gap Municipal Code 12.12.030, Use of public sewers required (Union Gap), quoted and re-checked
  5. Building Permit Application (Union Gap), quoted and re-checked
  6. RCW 18.27.090 — Exemptions (Washington statewide rule), quoted and re-checked
  7. Tiny Houses (Washington statewide rule), quoted and re-checked
  8. Union Gap Municipal Code 17.22.035, Manufactured home standards (Union Gap), quoted and re-checked
  9. Building | Community Development (Union Gap), quoted and re-checked
  10. Building | Community Development (Union Gap), quoted and re-checked
  11. City of Union Gap Community Development — Planning (uniongapwa.gov)
  12. Building a New Septic System, quoted and re-checked
  13. Septic Systems, quoted and re-checked
  14. Septic Alterations and Repairs (Union Gap), quoted and re-checked
  15. Union Gap Municipal Code 8.54.020, Unlawful camping (Union Gap), quoted and re-checked
  16. Planning & regulation — Washington State Department of Ecology (Washington statewide rule), quoted and re-checked
  17. Union Gap Municipal Code 17.14.050, Granting a Class (3) review (Union Gap), quoted and re-checked
  18. yakimacounty.us, quoted and re-checked
  19. RCW 47.32.150 — Approach roads, other appurtenances—Permit (Washington statewide rule), quoted and re-checked
  20. Groundwater permit exemption (Washington statewide rule), quoted and re-checked
  21. Zoning & Subdivision, quoted and re-checked
  22. Yakima County Code Title 19, Chapter 19.18, quoted and re-checked

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Union Gap

Union Gap’s own rules

  • Owner-builder exemptionConditional

    An owner acting as the owner's own contractor for a construction permit inside Union Gap city limits.

    • The owner must complete the city declaration.
    • The exemption is stated to be under RCW 18.27.090 and requires compliance with all conditions of that exemption.
    • If the owner uses assistance, only currently registered and licensed contractors may be retained as required by Washington law.
    • The declaration is made under penalty of perjury.
    “IF YOU ARE THE OWNER AND ACTING AS YOUR OWN CONTRACTOR, PLEASE COMPLETE THE FOLLOWING DECLARATION:”
  • Building code adoptedAdopted (with conditions)

    Construction inside Union Gap city limits.

    • The city follows the International Building, Mechanical, Plumbing, and Energy Codes as adopted and amended by Washington State.
    • The supplied municipal code also contains local amendments to the Washington State Residential Code.
    “Building compliance is achieved by following the International Building, Mechanical, Plumbing and Energy Codes as adopted and amended by the State of Washington.”
  • Zoning districtsPublished

    Union Gap zoning districts and permitted land uses inside city limits.

    • The table identifies R-1, R-2, R-3, R-4, C-1, C-2, CBD, W/W, L-I, PbF, PrC, and PkO districts.
    • Uses are designated Class 1, 2, or 3; blank means not permitted.
    • Some Class 1 uses may require Class 2 review.
    “Each permitted land use listed in Table 17.04.030 is designated a Class (1), (2), or (3) use for a particular zoning district.”
  • Camping on your landLimited

    Camping in public areas inside Union Gap city limits.

    • The prohibition has an exception where otherwise provided by code or where specifically designated by the owner of the property.
    • The cited section covers rights-of-way, trails, parks, park facilities, publicly owned parking lots, publicly owned areas, and public areas where camping obstructs or interferes with intended public use.
    • The cited section does not establish a general private-property camping rule.
    “It is unlawful for any person to camp in the following areas, except as otherwise provided by this code”
  • Manufactured homesLimited

    Manufactured homes inside Union Gap city limits.

    • Class A, B, and C manufactured homes are permitted within manufactured-home parks.
    • The permitted-land-use table separately lists manufactured homes by class and district; the supplied table excerpt does not preserve enough structure to map each class to every district.
    “Class-A, Class-B and Class-C manufactured homes are permitted within manufactured home parks.”
  • Who permits septicCounty (with conditions)

    On-site sewage systems inside Union Gap city limits; the municipal subdivision code identifies Yakima Health District as the administrator.

    • The administering body is the Yakima Health District, a county-area health authority.
    • The city code states that state and local on-site sewage standards are administered by the Yakima health district.
    “Our programs support safe food service, clean drinking water, safe septic systems, recreational safety, and other environmental health services across Yakima County.”
  • Septic inspectionRequired

    Septic alterations and repairs inside Union Gap city limits administered by Yakima Health District.

    • After installation, the installer and designer must prepare an as-built record.
    • YHD schedules a final inspection after the as-built is submitted.
    • YHD verifies that the installation matches the approved design and as-built record.
    “After the as-built has been submitted, YHD will schedule the final inspection.”
  • Off-grid sanitationProhibited

    On-site wastewater disposal inside Union Gap city limits.

    • The prohibition is subject to exceptions provided elsewhere in the chapter.
    • Where public sewer is within 200 feet of the property line and official notice is given, direct sewer connection is required.
    “Except as provided in this chapter, it shall be unlawful to construct or maintain any privy, privy vault, septic tank, cesspool”
  • Driveway accessLimited

    Development access and driveway points inside Union Gap city limits.

    • A Class 3 review may control the number and location of vehicular access points.
    • The supplied material does not establish a universal driveway permit requirement.
    “Control the number and location of vehicular access points;”
  • Permit feesVariable (with conditions)

    Building permits inside Union Gap city limits.

    • Fees depend on the valuation of work, cost per square foot, construction type, and use.
    • The city accepts cash, check, Visa, Mastercard, telephone payment, and online payment.
    “Building permit fees are based on the valuation of the work completed on the cost per square foot for the type of construction and use.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Union Gap or Yakima County directly.

  • Certificate of occupancy — Certificates of occupancy inside Union Gap city limits.
  • Minimum dwelling size — Residential districts inside Union Gap city limits.
  • Minimum lot size — Residential districts inside Union Gap city limits.
  • Setbacks — Residential districts inside Union Gap city limits.
  • Lot coverage — Residential districts inside Union Gap city limits.
6 more unanswered
  • Building height
  • Tiny homes
  • Accessory dwellings
  • Well permit
  • Agricultural exemption
  • Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Union Gap publishes no rule on the point, not that none exists. Yakima County’s page lists the county offices to call.

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