Boulder County commissioners have approved new limits on the size of homes in unincorporated parts of the county, in a move they say is aimed at addressing affordability concerns and reducing carbon emissions. The rules take effect May 13.
Commissioners have said that the new rules are not intended to address the region’s broader shortage of thousands of affordable housing units, but rather to curb the trend of increasingly large and costly homes in rural parts of the county.
The newly adopted amendment to the county’s site plan review process caps the size of new or expanded homes to the median floor area of a “defined neighborhood,” with limited exceptions. This replaces the previous allowance of up to 125% of the neighborhood median and eliminates several longstanding exceptions that allowed property owners to exceed the 125% limit.
The new rules include a sliding scale that allows some smaller homes to expand beyond the neighborhood median.
Homes destroyed in the 2021 Marshall Fire are exempt under a separate rule known as Article 19, which allows those properties to rebuild under the regulations in effect at the time of the fire. That exemption remains in place until March 2027.
With the amendment adopted, the commissioners also lifted a moratorium on new homes larger than the neighborhood median. That moratorium, which took effect in January 2025, imposed even stricter limits than those in the amendment.
Critics of the ordinance — including some property owners, architects and other professionals in the home building industry — said the regulations infringe on property rights and fail to reflect modern housing needs, such as space for home offices or multigenerational living. They also argued the use of neighborhood medians is inequitable, since residents of areas with larger homes can still build relatively large houses, while those in areas with smaller homes generally face tighter restrictions.
The county’s Planning Commission had recommended against adopting the changes, and instead urged commissioners to lift the moratorium and focus on alternative strategies, such as loosening rules for accessory dwelling units.
A majority of the three-member commission, however, voted for the amendment.
Commissioner Ashley Stolzmann described the changes as modest.
“One thing I am certain of is that this new code will provide a great deal of certainty,” Stolzmann said.
Commissioner Marta Loachamin said the amendment was intended in part to address the environmental impacts of the materials and resources required to build larger homes. She acknowledged the changes would not significantly affect the housing market but said they represent one piece of the county’s effort to improve affordability.
Commissioner Claire Levy voted against the amendment. She said she initially supported reviewing the policy due to the trend of increasing home sizes, but ultimately decided the changes would not meaningfully reduce housing costs.
“I think we’re really unnecessarily restricting what people can do,” Levy said.
Separately, City of Boulder councilmembers are weighing a new fee on homes that are demolished and replaced with larger ones. The fee would help fund the city’s affordable housing programs. The county does not impose such fees, though officials have said demolitions in unincorporated areas have often led to the construction of larger, presumably more expensive homes in their place.
Glad to see common sense prevail. We shouldn’t price out the next generation of small family farmers so that a small handful of the ultra wealthy can build their sprawling palaces unrestricted.
Telling residents they must limit their home sizes because of “environmental impacts,” yet allowing unbridled growth in the county. Doesn’t really matter if a house is 2K sq. ft. or 5k sq. ft. it it’s sited in what used to be farmland, fields or woods.
It was unfortunate and truly disappointing that the Commissioners did not respect the unanimous opposition by their own expert Planning Commission, by the numerous professionals who actually build homes in Boulder County, or by the vast majority of the public that came out strongly against these new rules. This is the biggest new restriction on property rights in Boulder in over 20 years, and yet many property owners in Boulder don’t even know this discussion was happening, as the County didn’t send out a notice to property owners. I guess people will find out when they try to expand their own home. There’s a mis-perception that this ordinance is designed to prevent “monster homes”. We don’t have an epidemic of those here. The new rules will prevent ordinary homes: If you have an existing old house in Boulder County, that has 1550 sf. above grade, plus a 7ft head height basement under it (another 1550 sf.) and a 3 car garage (900 sf.), according to BC, you have a 4000sf. house. Well, that sounds HUGE! But it’s not to you or to your neighbors. And now you want to add a ground floor handicapped accessible master bedroom so that you can age in place? Too bad.
Apparently, you already own a “Monster home” and can’t add more. The new rules will also make it hard for you to have sufficient space for kids or extended family, home offices or a lot of the other post-pandemic desires such as exercise, craft or media spaces.
The new rules will also hurt local businesses that serve homeowners looking to buy/sell, expand or build a home, as the new restrictions will make it harder for people to have the homes they need. It won’t improve sustainability as the Commissioner’s claim, as BC’s rules require that larger houses have stricter sustainability rules than smaller ones, and we already have the strictest sustainability codes in the Country. It won’t improve affordability either as restricting the supply of a handful new “larger” houses will make the existing supply thousands of larger houses more valuable and expensive. Lastly it won’t protect “neighborhood character” as County parcels tend to be giant; reducing a house from 4000 sf. to 3000 sf. will be visually imperceptible, especially as homeowners will now certainly choose to place as much of their precious remaining square footage above grade as possible. As their own Planning Commission stated “this was a solution looking for a problem.”
Thanks for sharing a more nuanced take Scott. It’s absurd to think that this will move the needle with respect affordability and will instead likely give rise to the series of unintended consequences you noted.
Yet another case of local governance ignoring feedback from those of us who actually live and work in unincorporated Boulder county, as well as their own bureaucracy.
This is a forward looking decision. It’s more important and environmentally sustainable to build smaller rather than continuously larger homes. It’s more important to provide more relatively affordable options for future homeowners than for existing homeowners to leverage their property wealth to create more wealth by building ever larger homes. People need to get over thinking they can do whatever they want wherever they want as long as they have money
Good for the county for passing this resolution. It’s the developers that want these large houses like Mr. Rodwin above they know they can make big money off these huge houses and also know there is no money in small reasonably priced housing. Mr. Rodwin seems to confuse the city in the county and his response, but regardless the city would never pass anything like this because the developers have the council wrapped around their little finger.