Where’s the water coming from? Part 1

May 12, 2019

When nearly every controversial housing project comes before the city, a well-intentioned but ill-informed citizen will throw out what they believe to be the ultimate well-informed argument-stopper and rhetorically ask: “But where’s the water coming from?”

It’s a legitimate question. Climate change effects on the Southwest and the Rio Grande watersheds are real. The long-term water supply is shrinking and will get worse. And because New Mexico grants water to those with the oldest claims, any new growth is last in the seniority line and first to have taps turned off.

But here’s the kicker: Not one new home built in Santa Fe in nearly 20 years has added even one gallon of new aggregate demand to the water supply. It sounds impossible. It’s intuitively and intellectually jarring, but it’s true. It’s true because of a couple of notions Santa Fe pioneered after the droughts of the late 1990s.

One notion was the “offset principle,” which said all new development, commercial or residential, must have zero impact on existing water availability. The second notion would be that a “water bank” would be established to track savings deposits and savings withdrawals. Our water savings bank is much different than what many places in the arid West do by “banking” and injecting water underground in aquifers or caverns for future use. Our bank is banking saved water.

A bit of history. Twenty years ago, we had over 14,000 acre-feet of water usage per year. Now we’re closer to 9,000 annually, even with all the growth of the past 20 years. That’s a savings of 5,000 acre-feet. What does one do with one’s savings? Puts it in a bank, of course, which is what the city created and did. For context, new residential construction assumes six newly built homes will consume one acre-foot of water per year.

How did we save that much water? Mainly by swapping out virtually every old toilet we could find. First, we gave out 10,000 low-flow toilets for free. Then we incentivized plumbers to literally knock on doors and beg homeowners to let them switch out their old toilets for free — or even sometimes even be paid for the privilege. Plumbers then took those saved-water credits and deposited them in the water bank. Then builders and developers came to the bank and purchased the saved-water credits to be used to offset the water the new home would use. Builders bought eight to 12 toilet credits for each new home, depending on lot size. In retrospect, builders were forced to buy even more savings credits than what new homes have consumed, which is why we’re still around 9,000 acre-feet even with our growth.

Does that mean we could conceivably build 30,000 new homes, at six per acre-foot, before we got back to the annual usage of 20 years ago? Theoretically, yes, but we can do even better. How to do so is the point of the third annual Next Generation Water Summit, to be held June 12-14 in Santa Fe.

Next week: Where’s the Water Coming From? Part 2

Kim Shanahan is a longtime Santa Fe builder and former executive officer of the Santa Fe Area Home Builders Association. He can be reached at shanafe @aol.com.