Longmont has one of the most permissive ADU programs in Colorado. Over 19,000 properties qualify. We know the rules, the zoning, and the approval process inside and out.
19,364
ADU-ready properties
Identified from Longmont parcel data
$1,800–$2,200
Estimated monthly rent
1-bedroom ADU, current Longmont market
500–750 SF
ADU size guaranteed by right
Per Colorado state law; larger with 50% rule
Longmont permits ADUs in most residential zones. The main constraints are lot coverage, setbacks, and the 50% rule. Our property finder checks all of these against your actual parcel.
Key requirements
Eligible zoning districts
R-SFSingle FamilyMost residential lots qualifyR-RURural / UrbanADUs permitted with standard setbacksR-MNMulti-NeighborhoodADUs permittedR-MFMulti-FamilyADUs permittedMU-DMixed Use DowntownADUs permittedMU-NMixed Use NeighborhoodADUs permittedMU-EMixed Use EmploymentADUs permitted in residential portionsN-AGNon-Urban AgricultureADUs permittedNot sure what zone you're in? The property finder shows your zoning automatically.
Check my propertyThe Longmont property finder uses real parcel data from Boulder County GIS and Longmont's building footprint records. Enter your address and see your actual lot, setbacks, and ADU placement options in 30 seconds.
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Keep exploring
Rental income potential
Real numbers on what ADUs earn in Longmont.
ADUs for family
Aging parents, multigenerational living, childcare.
How to finance an ADU
HELOC, construction loans, and CHFA options.
Process & timeline
What to expect from contract to move-in.
Floor plans & pricing
Three sizes, three tiers, two styles.
About Addwell
Who we are and how we build.