There’s no fence you can put up around the city and say, “No more people can live here.” However, cities in the Southwest face the very real prospect of saying, “No more people can live on the water we have here.”

"Water is the true limit to growth in the Southwest," says Kim Shanahan, executive officer of the Santa Fe Area Home Builders Association. "From the perspective of the home-building industry, it's really about how we are going to sustain our limited water resources into the future, or homebuilding won't exist in New Mexico and Arizona and California."

That reality makes the introduction of a water efficiency rating in Santa Fe's proposed update to its residential green building code among its more eye-catching revisions. In keeping with the city's role as a vanguard for water conservation, Santa Fe looks to be the first jurisdiction in America to craft a water efficiency score that combines indoor and outdoor water use—and as we learn each year in our top 10 water users story, often outdoor use is responsible for the bulk of consumption. If the ordinance passes City Council in October, homebuilders would be required to get a water efficiency rating score of 70, or 30 percent better than the water consumption rate from using standard building code. That's not a huge savings over current water consumption rates, says Katherine Mortimer, supervising planner with the city's land use department, but once it's clear the system works, councilors can set more stringent standards. The same goes for translating this code from single-family residences to commercial and multi-family development.

Other elements of the proposed revisions have raised some questions. Councilor Chris Rivera, reviewing it as part of Public Works Committee, abstained from voting over questions on the fiscal impact report. All other councilors on the committee voted to approve, and it likewise unanimously passed the Sustainable Santa Fe Commission.

These code revisions are expected to minimally affect on the cost of building a home in Santa Fe; their impact on carbon emissions and water consumption is similarly minimal, but just having the conversation is still a rarity.

"Across the country, you do not see this level of intentional thought on green building regulation in many jurisdictions, so a city that is trying to take this on is already a city ahead of the pack," says Jeremy Sigmon, US Green Building Council's director of technical policy.

After 25 years of encouraging "beyond code leadership" on an often voluntary basis for sustainable builders, he says, "There are large and looming local, regional and global environmental and health challenges that buildings can address, and we do need some sort of government fix to be able to square up the opportunity that green building presents with the risk of not doing it correctly."

The Santa Fe proposal ratchets down the existing required home energy rating system (HERS) index of 70 to 65 starting next year, then to 60 on Jan. 1, 2018. On average today, homes here score 61. Though the memo ties a possible $5,000 cost to this reduction, Shanahan disagrees with that analysis: "If the average is a 61, and we're going from a 70 to a 65, the average will not be impacted at all."

Mortimer agrees that $5,000 is a "worst case scenario" and points out that residents will recoup savings throughout the life of the home as efficiencies in water and electricity pay themselves back when prices for those utilities rise.

The citywide average is helped by construction from Homewise and Habitat for Humanity, Shanahan says. Homes built by those agencies often score in the 50s or even high 40s (the city doesn't have this analysis available). Larger homes struggle to reach a 70 score. With this update, homes over 3,000 square feet would need to score even lower than the new goal on HERS, by one point per 100 square feet.

Dropping by five points—though it varies widely from home to home—could be achieved by relatively inexpensive measures such as purchasing a more energy-efficient furnace, using all LED light bulbs, or removing one picture window. For some of those larger homes, yes, it could require the expense of installing solar panels to offset that northeastern-facing bank of picture windows.

In general, the revisions streamline the process by setting one performance-based goal, rather than providing a 33-page checklist of prescriptions. But the revisions increase demands on staff, the city says, to the tune of at least one more full-time employee and expected costs of $123,514 per year, including salary, benefits and equipment like a city-owned vehicle.

When the city decided to hold any current openings vacant through the fiscal year to balance the budget, they eliminated the position planned to take over these tasks, Lisa Martinez, land use director, said during the Public Works committee meeting.

"So now we're coming back and requesting that, should this plan move forward, we need to be realistic about how we're going to implement the program," she said. "We are really watching closely the permits coming in and starting to feel like we're going to have a real crunch on our hands."

With much of the development coming in the form of model homes, the city will only need to approve the handful of prototypes for and then rubberstamp any permits for that model, Shanahan says. He questions the need for a new position and worries the listed $5,000 and staffing needs could "scuttle the whole process."

"I would hate to see the city, because of a financial impact report, say we simply can't afford to do this because we can't afford to hire more personnel in a time of strain," he says.

Big picture analysis on how far off-track the city is on its goal of building net zero homes by 2030 and what this effort might do to get back on the rails also hasn't yet been completed.