Changes to Accessory Dwelling Unit Regulations in Boulder

Changes to Accessory Dwelling Unit Regulations in Boulder

When I was a Freshman at University of Wisconsin the Halloween celebration was the biggest gathering in the USA behind Time’s Square New Year’s Eve and Mardi Gras in New Orleans. 

It was terrifying. 

The bars all let out at the same time and the streets were packed with drunk college kids. What was a fun weekend turned into chaos – rocks being thrown at windows and police spraying pepper spray. 

The next year, instead of trying to police the situation more, the city took a different approach. They embraced the celebration – allowing bars to stay open all night long and bringing in flood lights to make the city feel like daytime all weekend. 

If you can’t stop it, embrace it.

That is in part, according to a city planner, the reason the Boulder City Council decided to loosen up regulations surrounding accessory dwelling units (additional living unit that has separate kitchen, sleeping, and bathroom facilities on a single-family lot). The city wanted to encourage all those homeowners with illegal ADUs to finally comply with the ADU regulations, and therefore city inspections. 

If you have an illegal ADU that you want to make legal or you want to add an ADU to your property – apply now. There are a limited amount of seats at this party.

The number of ADUs will be limited to no more than 20 percent of parcels – increased from the previous 10 percent – within 300 feet of a subject property (ADUs, cooperative housing units and non-conforming structures count in the saturation calculation.) But get ready for an arduous long process because the lights do not stay on all night over at Boulder City Planning and Development Office and they are short staffed and drowning in an increased number of ADU applications.

Here is the summary of the other big changes that went into effect on Feb. 1, 2019:

  • ADUs can be a larger size (800 square feet for a detached ADU and 1,000 square feet or one half the size of the principal home (whichever is less) for an attached ADU) and not provide the required additional parking previously required to get approval for an ADU in exchange for agreeing to limit rent to 75 percent of the Area Median Income based on the number of bedrooms. Currently that is about $1,835 for a 2 bedroom including utilities. 
  • The minimum lot size required was lowered from 6,000 square feet to 5,000 square feet for all types of ADUs.
  • The 5-year minimum age requirement for the primary home to create an ADU was done away with.
  • The occupancy limit has been increased. 
  •   Short-term rentals – like Airbnb – for newly created ADUs have been outlawed and owners that wish to create an ADU must forfeit a short-term rental license for the principal dwelling as well.

Once your ADU gets approved the permitting process or retro-permitting process begins.

So go add value to your property and head over to Boulder Planning and Development office – 1739 Broadway Boulder CO 80302 – to hurry up and wait. 

For more details about the new ADU regulations visit:

Good Good is a Boulder area real estate agency. We specialize in helping good people find the perfect Boulder home. We’re low pressure but high touch. If you’re looking for a real estate guide in the Boulder area, we may be a good fit. Give us a call if you’d like to chat. We’re always happy to answer any questions you have about the Boulder area or give you a tour. 

Thanks, Katie (Good Good Founder) | 720.415.4914|

1919 14th St.
Suite 700
Boulder, CO 80302

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