Monday night, the Calhan board of trustees narrowly approved a new ordinance limiting development in the town to a restrictive water supply standard.

The 4-3 decision directly impacts the prospects of a project called North Tree, which would bring about 475 single-family homes to undeveloped land in the town’s northwest corner. Calhan has a population of less than 800, so North Tree would drastically change the town’s makeup.

The town is about 45 minutes east of Colorado Springs, near the Paint Mines Interpretive Park and the county fairgrounds.

The ordinance adopts a 300-year water supply rule for the town. The rule affects the calculation of how much water per year a new development can draw from underground aquifers, some of which do not replenish. The idea is to limit draw to a rate that would be sustainable for 300 years.

The town’s new rule is in line with El Paso County, where Calhan is located, but stricter than the rest of the state. Colorado requires a 100-year water rule.

North Tree developers advocated for the less restrictive 100-year rule. A letter submitted to the town from the law firm of Smith Land Development, the company behind the project, argued that Calhan’s strong water rights portfolio made a 300-year rule unnecessary.

“There is no resource-based reason for the Town to hold itself to a standard stricter than the State’s,” the letter read.

Will Vandergriff, senior manager at Smith Land Development, declined to comment Monday night.

Some public speakers at the meeting advocated for conservation in water policy.

“We value our water because we don’t have a ton of it,” said Garrett Balsick.

How much water the town actually has physical access to is a question officials have been attempting to answer since North Tree came on the radar last year. Since Calhan has never seen a development on a similar scale, the town has not explored how much of its water rights its wells can produce.

In June, Moore Engineering, Inc. produced a report on tests it conducted at three town wells. Of the three, two were found to be deficient and not currently capable of pumping water at capacity.

The town can, with its functioning wells, produce about 200 to 225 acre-feet per year of water. An acre-foot is a unit of measurement equal to the amount of water needed to cover an acre a foot deep. The town has other water rights, however, and the engineering feasibility of those has not been explored.

For example, the report recommended that the town explore whether it could access its rights in the Upper Big Sandy alluvial aquifer, an underground source where the town could theoretically draw 118 acre-feet per year.

“Without further data, we conclude that this source will not provide a reliable water supply for the Town,” the report read.

North Tree representatives have indicated willingness to build new water infrastructure and add water rights to the town through the addition of the project’s 96 acres.

Monday night’s ordinance also sets standards for how much water residential and commercial projects will be expected to demand. North Tree developers got a number slightly out of their preferred range: 0.35 annual acre-feet for a single-family home instead of 0.25 to 0.30 acre-feet.

With more reports to come on how North Tree would affect infrastructure and services in Calhan, the annexation decision process is still ongoing.