Bolthole Index

Summit County, Colorado

Zoning, building permits and septic rules in the Town of Silverthorne, Colorado

The Town of Silverthorne, Colorado requires a building permit for new construction and sets its own zoning through its Community Development Department12. New building-permit applications in town are now routed to Comprehensive Building Code Services (CBCS) rather than Summit County3. Septic permits come from Summit County Environmental Health, not the town4.

At a glance

Building permit
Required in town; site plan approval comes first for site-plan districts, with single-family and duplex uses excepted1
Who handles building permits
Town Community Development; building-code review and inspections moving to CBCS3
Zoning
Town zone districts, administered by the Town25
Septic
Summit County Environmental Health issues septic (OWTS) permits countywide4
Accessory apartments
Conditional use; RVs and travel trailers cannot serve as the apartment6
Floodplain
Lowest floor must sit one foot above base flood elevation in mapped flood areas7
Tiny homes and RV living
Colorado approves tiny homes for long-term living only where local zoning allows; we could not confirm the town's RV or tiny-home rule8

Who to call

Building permits

Town of Silverthorne Community Development Department (building permits)

Building permit applications inside Silverthorne town limits; building-code review and inspections are moving to CBCS

(970) 262-7360

buildinginfo@silverthorne.org

Zoning

Town of Silverthorne Planning Department

Zoning, site plans, conditional use permits, variances and sign permits inside Silverthorne

(970) 262-7360

planning@silverthorne.org

Septic permits

Summit County Public Health — Environmental Health Division

Septic (OWTS) permits and inspections in Summit County

(970) 668-9161

360 Peak One Drive, Suite 230, Frisco, CO 80443

Contact details are copied from each office’s official page and were checked against it on October 16, 2026.

Off-grid gear

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

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Does Silverthorne have zoning, and what does it mean for RVs and tiny homes?

Yes. The Town of Silverthorne administers its own zone districts, and the town code ties site plans to those districts2. The code names C-2, C-1, RFMU, PUD, R-15, R-6, R-2, AG and O districts in its site-plan section, though we have not confirmed the full district schedule5. Zoning questions go to the town's Planning Department9. Rezonings, conditional use permits and variances are planning applications9.

On RVs, the one town rule we confirmed is narrow: mobile homes, RVs, camper buses and travel trailers cannot serve as an accessory apartment6. We could not confirm whether the town allows living in an RV on a lot, so ask the Planning Department before parking one. Colorado allows Division of Housing-approved tiny homes for long-term living, but only where local zoning permits them8. The town's own tiny-home rule is unconfirmed; ask Planning.

Do you need a building permit in Silverthorne, and who issues it?

Yes. The town code bars issuing a building permit for new buildings or additions in site-plan districts until the site plan is approved1. Single-family and duplex uses are excepted from site plan review in the listed districts1. Building permits for single-family homes and small projects do not need Planning Commission or Town Council review3.

The town's Community Development Department takes building permit requests by appointment only3. Since July 14, 2026, new applications and revisions are routed to Comprehensive Building Code Services (CBCS), and inspections other than electrical shift to CBCS on August 17, 20263. Applications already under review stay with Summit County's review until complete3. Summit County Building Inspection serves unincorporated land; for the county's rules see the Summit County page. A certificate of occupancy for site-plan projects is not issued until approved improvements are complete, and no temporary certificate is allowed10.

How do septic permits work in Silverthorne?

The town does not issue septic permits. Summit County Environmental Health issues onsite wastewater (OWTS) permits and inspects new systems and repairs across Summit County4. Colorado law requires a permit from the local public health agency before anyone builds or alters an OWTS11. The county's septic rule covers septic systems, so properties served by public sewage treatment fall outside it12.

We could not confirm whether every lot inside Silverthorne is sewered, so ask the Environmental Health Division before you buy a lot you expect to put on septic13. Wells are a separate state permit: every new well that diverts groundwater needs a permit from the Division of Water Resources14. Whether a well is allowed on a particular town lot is unconfirmed.

Can you build an accessory apartment in Silverthorne?

Silverthorne allows a single apartment on a single-family lot as a conditional use after staff approval6. The apartment's floor area cannot exceed 33 percent of the single-family dwelling6. Only one is allowed per lot, the owner must live on the property, and the minimum lease is six months6. The town also requires an HOA approval letter, system development fees and enough off-street parking6. Short-term rental of the property is not allowed6. The Planning Department handles the single apartment conditional use permit9.

How do you build a home in Silverthorne, step by step?

  1. Confirm the zone district and what it allows with the Planning Department9.
  2. Check the flood map: in special flood hazard areas, the lowest floor must be elevated one foot above base flood elevation, certified by a Colorado engineer, architect or surveyor7.
  3. If your project is in a site-plan district, get the site plan approved first1.
  4. Book an appointment with Community Development and submit the building permit application, which is now routed to CBCS3.
  5. If the lot is not on public sewer, apply for an OWTS permit with Summit County Environmental Health4.
  6. Pass inspections and obtain the certificate of occupancy10.

What stays with Summit County, and what should you check before buying in Silverthorne?

The county decides septic permits4. Summit County's own building, zoning and short-term-rental rules apply to unincorporated land, not to lots inside the town15. The county's short-term-rental license excludes incorporated towns16. Silverthorne's rental rules sit in its own code, which we could not confirm.

Budget realistically: Summit County's typical home value is about $984,77417, and its effective property tax rate is 0.3%18. A driveway onto a state highway needs a state access permit19.

Watch-outs

  • Building-department services changed in 2026: new applications go to CBCS and most inspections move on August 17, 2026, so confirm with Community Development who reviews your project3.
  • Summit County's rules for unincorporated land do not apply inside town limits15.
  • We could not confirm the town's minimum lot sizes, setbacks, heights, RV, tiny-home, well or short-term-rental rules; ask the Planning Department9.
  • Building code details for the town and owner-builder rules inside town are unconfirmed; call Community Development before pulling permits yourself3.

Sources

  1. Silverthorne Municipal Code Sec. 4-6-2 General requirements (site plan) (Town of Silverthorne), quoted and re-checked
  2. Silverthorne Municipal Code Sec. 4-6-2 General requirements (site plan) (Town of Silverthorne), quoted and re-checked
  3. Town of Silverthorne Community Development Department (building permits) (silverthorne.org)
  4. Onsite Wastewater Treatment Systems (OWTS), quoted and re-checked
  5. Silverthorne Municipal Code Sec. 4-6-2 General requirements (site plan) (Town of Silverthorne), quoted and re-checked
  6. Silverthorne Municipal Code Sec. 4-4-21 Single apartments (Town of Silverthorne), quoted and re-checked
  7. Silverthorne Municipal Code Sec. 3-8-20 Specific standards (flood damage prevention) (Town of Silverthorne), quoted and re-checked
  8. Consumers of Manufactured Homes and Tiny Homes - HUD (Colorado statewide rule), quoted and re-checked
  9. Town of Silverthorne Planning Department (silverthorne.org)
  10. Silverthorne Municipal Code Sec. 4-6-2 General requirements (site plan) (Town of Silverthorne), quoted and re-checked
  11. Title 25 - Public Health and Environment - Colorado Revised Statutes 2024 (Colorado statewide rule), quoted and re-checked
  12. Onsite Wastewater Treatment Systems (OWTS), quoted and re-checked
  13. Summit County Public Health — Environmental Health Division (summitcountyco.gov)
  14. Water Administration (Colorado statewide rule), quoted and re-checked
  15. Single-Family Building Permit Checklist, quoted and re-checked
  16. Short-Term Rentals, quoted and re-checked
  17. Typical home value (Zillow): Bolthole Index county data
  18. Effective property tax rate: Bolthole Index county data
  19. Access Permits | Frequently Asked Questions (Colorado statewide rule), quoted and re-checked

Written October 16, 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 Town of Silverthorne

Town of Silverthorne’s own rules

  • Building permitRequired

    New buildings in site-plan-regulated zone districts inside Silverthorne town

    • Site plan approval must precede building permit issuance for uses in Sec. 4-6-2(a); single-family and duplex uses are excepted from site plan review in listed districts.
    “no building permit for any use described in subsection (a) above shall be issued for the construction of any new building, structure or improvement to the site or any addition or alteration to the structure or site, including exterior materials or colors, without first obtaining the approval of a site plan for the proposed use.”
  • Certificate of occupancyRequired

    Site-plan projects inside Silverthorne town

    • No temporary certificate of occupancy is permitted for site-plan projects.
    • Issued only after approved improvements are complete or security is received under Sec. 4-6-9.
    “no certificate of occupancy will be issued until all improvements approved as part of the site plan have been completed or necessary security received as described in section 4-6-9 of this article. no temporary certificate of occupancy shall be permitted.”
  • Local zoningPresent

    Land inside Silverthorne town limits

    • Town code refers to zone districts and zoning district standards administered by the Town.
    “no site plan application shall be accepted which does not meet all zoning district standards.”
  • Zoning districtsPartial

    Zone districts inside Silverthorne town

    • Sec. 4-6-2(a)(1) names C-2, C-1, RFMU, PUD, R-15, R-6, R-2, AG and O districts; full district schedule not opened.
    “all uses located within the following zone districts, with the exception of duplex- and single-family residential:”
  • Accessory dwellingsLimited

    Single apartments (accessory units) on single-family lots inside Silverthorne town

    • Floor area not more than 33% of single family dwelling
    • Only one per lot; owner must maintain continuous residency
    • Minimum six-month lease
    • HOA approval letter and system development fees required
    • No short term rental on property
    • Mobile homes, RVs, camper busses and travel trailers cannot be used as single apartments
    • Must be built within footprint or integral part of detached building on same lot
    • Sufficient off-street parking

    max apartment floor area share: <= 33 percent of dwelling floor area (attached garage may be counted in dwelling floor area)

    “single apartments may be allowed as a conditional use after receiving staff approval of a single apartment conditional use under article vii of this chapter.”
  • Building in a floodplainRequired

    Special Flood Hazard Areas inside Silverthorne town

    • Applies where base flood elevation data has been provided
    • Lowest floor elevated one foot above base flood elevation, certified by Colorado PE, architect or surveyor
    • RVs must be on site fewer than 180 consecutive days, be highway-ready, or meet permit and elevation requirements

    freeboard above base flood elevation: >= 1 foot

    “in all special flood hazard areas where base flood elevation data has been provided as set forth in section 3-8-7, paragraph 3-8-15 (7) or section 3-8-24 of this article, the following provisions are required: (a) residential construction. new construction and substantial improvement of any residential structure shall have the lowest floor (including basement) and any electrical, heating, ventilation, plumbing, and air conditioning equipment and/or other service facilities (including ductwork) elevated to one (1) foot above the base flood elevation.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Town of Silverthorne or Summit County directly.

  • Owner-builder exemption — Owner-builder inside Silverthorne town
  • Building code adopted — Building code inside Silverthorne town
  • Inspections — Building inspections inside Silverthorne town
  • Minimum dwelling size — Minimum dwelling size inside Silverthorne town
  • Minimum lot size — Minimum lot size in R-6/R-15/AG inside Silverthorne town
19 more unanswered
  • Setbacks
  • Lot coverage
  • Building height
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Driveway access
  • Short-term rentals
  • Permit fees
  • Permit process

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 Town of Silverthorne publishes no rule on the point, not that none exists. Summit County’s page lists the county offices to call.

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