Building permits, zoning and septic rules in the Town of Lyons, Colorado

At a glance

Building permit

Required inside Lyons; sheds of 120 sq ft or less are exempt¹

Who issues building permits

The Town of Lyons, through its contracted building department³

Zoning

Town zoning, including A-1 and A-2 agricultural districts²

A-2 minimum lot

35 acres, one dwelling per 35 acres⁵

Height limit (A-1, A-2)

30 feet⁶⁷

Septic

Boulder County Public Health rules govern onsite systems in the county; the in-town process is unconfirmed⁴

RV living

Only by temporary permit on public streets, up to 10 days; private-lot rules unconfirmed⁸

Tiny homes

Tiny homes on wheels may be ADUs up to 400 sq ft with administrative approval⁹

Who to call

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

Does Lyons have zoning, and what does it mean for RVs, tiny homes, lot size and setbacks?

Yes. The Town of Lyons adopts its own zoning in Chapter 16 of the municipal code, and the Planning Department oversees it²¹⁰. The A-1 district is a low-density district intended for farm activities². In the A-2 district the minimum lot area is 35 acres, with one dwelling unit per 35 acres and a minimum lot width of 300 feet⁵.

Both agricultural districts cap buildings at 30 feet⁶⁷. Side yards in A-1 and A-2 are 10 feet plus one foot for each two feet of building height, and the front yard is at least 30 feet¹¹¹².

A tiny home on wheels can serve as an accessory dwelling unit in Lyons' R-1, R-2, R-2A and A districts with administrative approval, up to 400 square feet and 17 feet tall, if it is certified manufacturer-built⁹. Lyons allows one accessory dwelling unit per lot, and a second on lots of half an acre or more; mobile and manufactured homes and RVs cannot be accessory dwelling units¹³. Manufactured home parks need a PUD-MH overlay¹⁴.

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

Yes. Building work inside Lyons town limits requires a building permit, with an exemption for one-story detached sheds and playhouses of 120 square feet or less, a roof height of 10 feet or less, and a spot 10 feet or more from the nearest occupiable structure¹. Starting work before getting a permit can bring an investigation fee of up to the permit fee¹.

Lyons has adopted the International Residential Code with local amendments¹⁵. Inspections apply to permitted work, including an insulation inspection before wall coverings go up¹⁶. In wildland-urban interface areas the Colorado Wildfire Resiliency Code applies¹⁵.

The Town of Lyons contracts with SafeBuilt to run its building department, and building permit applications are made online through an account in Community Core³. Building permit fee and tax schedules are posted on the same town page; we did not confirm the amounts.

How do septic permits work inside Lyons?

We could not confirm who issues septic permits for a lot inside Lyons or how the town's sewer service applies to a given address. Colorado law requires a permit from the local public health agency before anyone constructs, alters or installs an onsite wastewater treatment system¹⁷. In Boulder County, Boulder County Public Health regulations govern all onsite wastewater treatment systems in the county¹⁸.

The town's building and planning offices do not appear to issue septic permits. Before buying a lot in Lyons, ask the Town of Lyons whether the lot can connect to town sewer, and ask Boulder County Public Health's SepticSmart Program at 303-441-1564 about any lot that cannot¹⁸.

Wells are a state matter: every new groundwater-diverting well in Colorado needs a state permit, subject to exemptions and basin-specific rules¹⁹. Whether Lyons allows a private well on a town lot is unconfirmed.

Can you live in an RV or tiny home in Lyons?

Camping in a recreational vehicle in Lyons is allowed only by temporary permit from the town administrator, and the rules we found cover public streets, right-of-way and town property⁸. Such a permit is valid for up to 10 days, with a maximum of two per property per calendar year, and the RV must sit directly adjacent to property where the applicant has permission to park⁸. We did not find a rule for living in an RV on a private lot, so ask the Planning Department before assuming it is allowed.

Tiny homes are treated as accessory dwellings: a certified tiny home on wheels may be approved as an accessory dwelling unit of up to 400 square feet⁹. Manufactured homes cannot serve as accessory dwellings and are limited to permitted parks¹⁴.

Building a home in Lyons: the steps, in order

1. Confirm the lot's zoning district and setbacks with the Planning Department, and ask for a pre-application meeting before any application¹⁰.
2. Check the lot against the floodplain rules: in a Special Flood Hazard Area the lowest floor of a new residence must be elevated two feet above base flood elevation²⁰.
3. Ask the town about sewer and water connection, and Boulder County Public Health about septic if no sewer is available¹⁸.
4. Create an account in Community Core and apply for the building permit through the town's contracted building department³.
5. Schedule inspections, including the insulation inspection before wall coverings are installed¹⁶.
6. Ask the building department about a certificate of occupancy; we could not confirm the town's process.

What stays with Boulder County, and what to check before you buy in Lyons?

The town's rules apply only inside Lyons town limits. Land outside the limits is unincorporated Boulder County, where the county issues building permits and sets zoning; see the Boulder County page for those answers²¹²². Outside town limits the county also treats permanent RV living as prohibited²³.

Septic regulation is countywide through Boulder County Public Health⁴. Boulder County's typical home value is $727,688²⁴ and its effective property tax rate is 0.5%²⁵; both are county figures, not Lyons-specific. Only 8.4% of Boulder County soils rate as not limited for a conventional septic drain field, so expect a site evaluation or an engineered system on a lot without sewer²⁶.

Watch-outs

• Floodplain standards in Lyons apply to activity after October 24, 2024, and RVs in flood zones must be on site fewer than 180 days, highway-ready, or permitted²⁰.
• The Colorado Wildfire Resiliency Code applies in Lyons' wildland-urban interface areas to conditions arising after June 30, 2026¹⁵.
• We could not confirm Lyons' septic permit process, well rules, owner-builder rules, permit fee amounts or driveway permit rules; call the Town of Lyons at 303-823-6622³.
• Do not apply Boulder County's unincorporated-area building or zoning answers to a lot inside Lyons: the town decides those inside its limits².

Sources

1. Lyons Sec. 18-3-40 Residential Code modifications (Town of Lyons), quoted and re-checked
2. Lyons Sec. 16-3-110 A-1 Agricultural District (Town of Lyons), quoted and re-checked
3. Town of Lyons Building Department (contracted to SafeBuilt) (townoflyons.com)
4. OWTS Permits and Fees - Boulder County, quoted and re-checked
5. Lyons Sec. 16-3-120 A-2 Agricultural District (Town of Lyons), quoted and re-checked
6. Lyons Sec. 16-3-110 A-1 Agricultural District (Town of Lyons), quoted and re-checked
7. Lyons Sec. 16-3-120 A-2 Agricultural District (Town of Lyons), quoted and re-checked
8. Lyons Sec. 8-4-10 Parking prohibited (Town of Lyons), quoted and re-checked
9. Lyons Sec. 16-10-70 Accessory dwelling units (Town of Lyons), quoted and re-checked
10. Town of Lyons Planning Department (townoflyons.com)
11. Lyons Sec. 16-3-110 A-1 Agricultural District (Town of Lyons), quoted and re-checked
12. Lyons Sec. 16-3-120 A-2 Agricultural District (Town of Lyons), quoted and re-checked
13. Lyons Sec. 16-10-70 Accessory dwelling units (Town of Lyons), quoted and re-checked
14. Lyons Sec. 16-4-30 Manufactured home parks (Town of Lyons), quoted and re-checked
15. Lyons Sec. 18-3-40 Residential Code modifications (Town of Lyons), quoted and re-checked
16. Lyons Sec. 18-3-40 Residential Code modifications (Town of Lyons), quoted and re-checked
17. Title 25 - Public Health and Environment - Colorado Revised Statutes 2024 (Colorado statewide rule), quoted and re-checked
18. Boulder County Public Health SepticSmart Program (bouldercounty.gov)
19. Water Administration (Colorado statewide rule), quoted and re-checked
20. Lyons Sec. 18-15-370 Standards for subdivision proposals (Town of Lyons), quoted and re-checked
21. Building Permits - Boulder County, quoted and re-checked
22. Land Use Code - Boulder County, quoted and re-checked
23. Planning FAQ - Boulder County, quoted and re-checked
24. Typical home value (Zillow): Bolthole Index county data
25. Effective property tax rate: Bolthole Index county data
26. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data

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.