Boulder is poised to restrict daytime lawn watering for all residents and businesses, one of several updates to the city’s landscaping standards aimed at conserving water and boosting wildfire resilience.
The changes are part of Boulder’s first major update to its landscaping rules in more than two decades, under the city’s Waterwise Landscaping Project.
Under the proposal, watering lawns between 10 a.m. and 6 p.m. would be prohibited citywide, when the most irrigation water is lost to evaporation.
“[The water’s] not being used, it’s just a waste of money,” Karl Guiler, a city planner overseeing the project, told Boulder Reporting Lab. “So people hopefully will start to understand that.”
Exceptions would be allowed for large properties with documented pressure issues, newly planted landscaping during the first 30 days after installation, hand-watering of trees or plants with a hose and shut-off nozzle, areas used for urban agriculture or food production, and irrigation system maintenance or repair.
The watering restriction would be among the most visible parts of the broader effort to cut water waste and make properties more fire-resilient as climate conditions grow hotter and drier. Most of the new requirements, such as plant and turf rules, would apply only to new construction and major renovations.
The proposed ordinance would ban decorative turf that serves no practical purpose, such as narrow strips of grass along sidewalks or in parking medians, while still allowing grass in functional areas like dog parks, sports fields and picnic spaces. These limits on non-functional turf would apply to new commercial, institutional, industrial and common-interest community properties, as well as new residential projects with three or more units.
The proposed rules allow drought-tolerant, fire-resistant plants — such as sulphur buckwheat, western yarrow and blue flax — and ban high-water species like Kentucky bluegrass in most new developments. Bluegrass would still be permitted in designated “functional” areas, such as parks and recreation fields.
“Plants play a big part in trying to conserve water, but also in trying to deter the spread of wildfire,” Guiler said.
City council will hold a public hearing on the landscaping updates on Oct. 16, with a formal vote expected later this fall.
The plant-related changes complement a separate home-hardening ordinance that took effect in August. That measure requires new homes and major remodels in the wildland-urban interface to use fire-resistant materials and bans flammable plants like junipers and other materials within five feet of structures.
Together, the two ordinances aim to better protect new properties from the threat of wildfire. But they’re already sparking debate — and have become a prevalent topic on the city council campaign trail — because they would need to apply to existing homes to make a real difference.
During the Marshall Fire, embers carried by wind ignited vegetation and fences, helping spread the blaze that destroyed more than 1,000 homes. Boulder fire officials have said it’s not a matter of if but when a fire takes hold in Boulder proper. The city expanded its designated wildland-urban interface earlier this year to better reflect where that risk exists across the city.
Weighing water savings and costs
Beyond wildfire safety, city officials say the new rules are about changing how Boulder uses water. The Waterwise project aims to cut waste from lawns and promote native, low-maintenance plants suited to Colorado’s climate.
“We live in a dry climate, but people have been building neighborhoods much like they do in the East, where there’s a lot more water,” Guiler said. Common grasses like Kentucky bluegrass, often used in commercial developments or along transportation corridors, require large amounts of water to maintain.
“It’s just grass you look at,” Guiler added. “You should be using more native grasses that don’t need as much water.”
A state law prohibiting non-functional turf will take effect in 2026, and Boulder’s landscaping rules would bring the city into compliance.
The ordinance would also streamline future updates to Boulder’s landscaping rules. Instead of embedding technical details directly into the city code, those standards would be moved into a landscaping manual governed by a city manager rule, a change meant to make it easier to make updates easier as new research and climate priorities emerge.
“It’s still a public process, there’s public feedback involved, but changes can be made to the manual a lot faster,” Guiler said.
The new code would also apply to major home renovations or additions that require building permits. What counts as “major,” however, is still under discussion. Currently, a project must equal or exceed 75% of the property’s valuation to trigger landscaping requirements. Staff have proposed lowering that threshold to 50% to broaden the ordinance’s impact, as city councilmembers have voiced concern that the measures won’t cover enough houses to create tangible effects.
“There’s a balance,” Guiler said. “We want to make sure we’re getting enough properties to meet the goals of the [waterwise] project, but we also have to be mindful of cost.”
The Planning Board voted 3-2 in support of recommending the landscaping ordinance to the city council, but that failed to meet the threshold to actually approve the recommendation. One member raised concerns that it could negatively affect residential food gardens and inadvertently lead to less vegetation. “I am not convinced that the proposed ordinance has figured out an appropriate balance of fire mitigation, water saving and cooling strategies,” said board member Claudia Hanson Thiem.
The proposal has also raised some concerns among city councilmembers. Mayor Pro Tem Lauren Folkerts, writing on the council Hotline, said she supports the goal of creating more climate-resilient landscapes but worries the ordinance could have unintended consequences.
She said it might “increase our urban heat island effect by removing too much vegetation and shade” and doesn’t fully address how to make landscaping for affordable housing and commercial projects more cost-effective and durable. Folkerts also cautioned that the new rules could “add another layer of complexity to the permitting process,” leading to more delays and unpermitted work.
Planning Board member ml Robles has also urged the city to include allowing graywater reuse — lightly used water from showers or washing machines that can be treated and reused for underground irrigation or flushing toilets — in the landscaping ordinance. Boulder’s proposal does not mention graywater. In fact, city staff have introduced a separate ordinance to opt out of a new state law requiring cities to allow such systems. Staff say Boulder lacks the capacity to regulate graywater at this time, but could revisit the issue in the future.
A first reading of that ordinance by city council is also scheduled for Oct. 16, with a second reading set for Nov. 6.
These new landscape restrictions will be upending gardens (see the height restrictions). What is the deal with making weed block illegal? will they come weed my garden for free? Landscape architects and annual arborist visitations are not inexpensive…. And why is Boulder so against grey water re-use? there is water savings in that right there. Stop building so many apartments (many do not pay individually for water so they can use as much as they want). I understand the evaporation— common sense. But The city is becoming a giant HOA. There are bigger and more important things to address….
I find it interesting that there does not appear to be consideration of the source of water used for sprinkling and irrigation. There are a significant number of folks in Boulder who obtain water for sprinkling and irrigation from several irrigation ditches , or from privately owned wells, and their ability to use water from these independent sources should be addressed clearly. Irrigation ditches are a major amenity for Boulder in aesthetic and practical terms, and the impact of the proposed regulations may have a significant impact how they can continue to function. For example – some ditch users receive their water only during the daytime hours, and do not have access to their water at other times. If they lose the ability to use their water, they are likely to stop participation in their ditch maintenance and management, as some of the ditches are owned and maintained by their users.
The city benefits by using these ditches to supply lakes (including Wonderland Lake, Maxwell Pond, and Mesa Reservoir among others) and irrigation for parks (including, for example Foothills Community Park). Irrigation ditches and laterals also are a major factor in functional and attractive tree cover in the irrigation service areas.
Although the objective of diminishing and/or limiting water use is reasonable, it is not clear to me that sufficient consideration has been given to avoid the unintended consequences of this proposed ordinance.
Where and what time on Oct 16th?? Would be quite helpful to know.
Lois LaCroix