By Prerna Kapoor, CLHMS | REAL Brokerage | August 7, 2026
I get a version of the same question from almost every buyer who’s looking seriously at Castle Rock: is the water actually going to be there in twenty years? It’s a fair thing to wonder about a town that’s growing as fast as this one is. So let’s go through what’s actually happening, not the rumor-mill version.
The Math Behind Castle Rock’s Water Situation
Castle Rock Water currently serves around 90,000 residents, and the town’s population is expected to nearly double by 2050. Right now, only about a third of the water used in Castle Rock comes from renewable sources. The town goes through more than 3.2 billion gallons a year, and most of that is pulled from the Denver Basin aquifers deep underground.
That’s not the crisis it sounds like. It’s actually one of Castle Rock’s real advantages. Groundwater doesn’t disappear during a drought year the way a river or a reservoir can. But it’s still a finite resource, and Castle Rock Water director Mark Marlowe has said it plainly: the aquifer needs to be protected for the long haul, not treated as an endless supply. That’s the whole reason behind the renewable water push you’ll see below.
What Castle Rock Water Is Actually Building
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This part matters if you want to know whether the plans are real or just talk. Castle Rock Water is expanding the Plum Creek Water Purification Facility, doubling its capacity from 6 million gallons a day to 12 million, at a cost of about $75 million. The town has also completed two new reservoirs, roughly $28 million combined, that store water collected in wetter years for when it’s needed later. Together those reservoirs cover about a tenth of Castle Rock’s total annual water needs.
On top of that, the utility has spent about $29 million on land and water rights up in Weld County, expected to secure 2,500 acre-feet once that project wraps up around 2030. Add in the regional WISE partnership, the Platte Valley Water Partnership, and a growing reuse program the utility expects will eventually make up roughly a third of its long-term supply, and you get a picture of a utility that’s actively building toward its stated goal: 100% renewable supply in an average year by 2065, with groundwater held in reserve for drought years.
If You’re Buying New Construction
Here’s the part that actually affects your closing costs. Builders currently pay roughly $44,000 per home in system development fees just to connect to Castle Rock Water’s infrastructure, and that gets built into the price of every new home. It’s a real number worth asking about when you’re comparing a new build in Castle Rock to a new build in a metro district elsewhere in Douglas County, since those come with their own separate tax structure on top of whatever the local water utility charges.
You’ll also notice something if you’ve toured new construction here recently: front yards in new developments can’t have turf grass anymore. The town requires low-water landscaping instead, rock beds, native plantings, drip irrigation. If you were picturing a classic green lawn out front, that’s worth knowing before you fall for a floor plan.
If You’re Buying Resale or Already Own
Rate increases are happening gradually here, not all at once. Castle Rock Water reviews its rates and fees annually rather than issuing sudden shocks to the budget. If you’re on an older lawn that predates the new landscaping rules, there’s a real incentive to switch: a $3.25 per square foot rebate for replacing high-water turf with drought-tolerant landscaping, which is one of the better turf replacement programs anywhere in Colorado.
Castle Rock is also targeting a 20% cut in per-capita water use between now and 2050. Practically speaking, that means you should expect more conservation messaging and probably more rebate programs over time, not fewer. If water rights and supply reliability are a bigger concern for you generally as a Colorado buyer, our water rights guide goes deeper into how that works statewide.
Quick answers
Is Castle Rock going to run out of water?
Not based on what the utility is currently planning for. The town’s groundwater reserves provide real drought resilience, and officials are actively investing in renewable supply to reduce dependence on that groundwater over time, rather than waiting for a shortage to force the issue.
How much does the water infrastructure add to a new home in Castle Rock?
Builders currently pay about $44,000 per home in system development fees, which gets factored into the price you’re quoted. It’s one reason new construction can cost more upfront than a comparable resale home.
Can I still have a grass lawn?
Backyards generally still allow turf. It’s front yards in new developments where low-water landscaping is now required, and the town offers a $3.25 per square foot rebate if you want to convert an existing lawn voluntarily.
If you’re weighing Castle Rock against the rest of the neighborhood or against Parker or Highlands Ranch, and want to talk through what any of this actually means for your budget, I’m always happy to walk through it with you. No pressure, no pitch. For general Colorado buying and selling questions, our Colorado Real Estate FAQ is a good place to start too.
Prerna Kapoor | REALTOR® | Luxury Home Specialist
REAL Brokerage | 720-949-5450 | info@prernakapoor.com
CLHMS • RENE • PSA • ABR | International Sterling Society Award Winner
Prerna specializes in residential real estate across Parker, Aurora, Lone Tree, Castle Pines, Highlands Ranch, Cherry Creek, Greenwood Village, and Centennial. She speaks English, Japanese, and Hindi.
