What do buyers need to know about wells and septic systems in Custer County, Colorado?
Almost every rural property in Custer County runs on a private well and an on-site septic system instead of municipal water and sewer. Before you close, you need a permitted, working septic system (governed by Custer County’s OWTS regulations) and a clear picture of the well’s permit, yield, and water quality. Skipping either check is how buyers end up with a $15,000–$25,000 surprise right after closing.
By Kayla Brady | August 17, 2026
If you’re used to city utilities, this is the biggest mental shift in buying land, a cabin, or a ranch out here. There’s no water department to call and no sewer bill. You own the whole system — the well that brings water in and the septic system that takes wastewater out — and you’re responsible for both working correctly.
I walk almost every buyer through this before we write an offer, because it changes what due diligence actually means on a rural property.
Septic Systems: What’s Actually Required
Colorado regulates septic systems — officially called On-Site Wastewater Treatment Systems, or OWTS — at the county level under the state’s Regulation 43. Custer County has its own OWTS regulations that spell out permitting, design, and inspection requirements for the county.
Here’s what that means in practice:
- No permit, no dwelling. Custer County won’t issue a zoning permit for a residence without a valid septic permit already in place. If you’re buying land to build on, this is one of the first things to confirm before you commit.
- New installations and major repairs need an engineered design. Certain soil types, slope, or a high water table can trigger a requirement for a licensed engineer to design the system.
- Occupying a property without an approved septic system is not allowed — even occasionally, even in an RV. This matters if you’re eyeing a property with an older or unpermitted system and picturing weekend use in the meantime.
- Transfer-of-title inspection rules vary by county in Colorado, and requirements can change. Don’t assume your last transaction’s rules apply here — confirm directly with the Custer County Planning & Zoning office whether an inspection or use permit is required for your specific sale before you get near closing.
Wells: The Other Half of the Picture
Most homes here rely on a permitted groundwater well, and many fall under Colorado’s domestic well exemption — limited household use allowed without a fully adjudicated water right, subject to pumping limits set by the state. If you want the full breakdown of how water rights work in this market, that’s a deeper topic on its own — ask me and I’ll walk you through it.
For a well specifically, here’s what buyers should check before removing contingencies:
- Well permit on file — confirm it exists and matches how the property is actually being used
- Yield test — how many gallons per minute the well actually produces, especially important for horse properties or anything with irrigation needs
- Water quality test — bacteria, nitrates, and, in some parts of the county, naturally occurring minerals worth knowing about before you’re drinking it daily
- Pump and equipment condition — a functioning permit doesn’t tell you whether the pump itself is nearing the end of its life
What This Means for Your Offer
A property with a documented, permitted septic system and a well with a clean recent water test is simply worth more — and safer to buy — than one where you’re taking the seller’s word for it.
Before you get too far into a deal on land, a cabin, or a ranch in Custer County:
- Ask for the septic permit and any inspection or pumping records up front
- Ask for the well permit number and recent water quality results, if available
- Budget for your own septic inspection and well test as part of your due diligence period, not as an afterthought
- If anything comes back unclear, use it as a real negotiating point — a repair credit or price adjustment, not just a walk-away decision
Every property here is different, and the age of the system, the number of bedrooms it’s rated for, and the soil conditions all change what you actually need to check. That’s exactly the kind of walk-through I do with buyers before they write an offer on rural property.
Sellers: Get Ahead of This Before You List
If you’re selling, the same systems that protect buyers can slow down or derail your closing if you haven’t checked them first. Colorado’s Seller’s Property Disclosure requires you to disclose known septic and well issues, and an unpermitted or aging system discovered mid-contract is one of the most common reasons rural deals in this market fall apart or get renegotiated at the last minute.
Getting your septic system inspected and your well tested before you list — not after an offer comes in — gives you time to fix small issues on your own terms instead of under contract deadline pressure.
Frequently Asked Questions
Do I need a septic inspection to sell my house in Custer County?
Requirements vary by county in Colorado, and they can change. Confirm current requirements directly with Custer County Planning & Zoning or Environmental Health before you list, rather than assuming based on a past sale elsewhere.
Can I build on land in Custer County without an approved septic system?
No. The county will not issue a zoning permit for a dwelling without a valid septic permit already in place, and occupying a structure without an approved system is not allowed, even occasionally.
How much does a septic inspection cost in Colorado?
Septic inspections by certified contractors typically run a few hundred dollars, though costs vary depending on the system type and whether pumping is included as part of the inspection.
What’s the difference between a septic permit and a septic inspection?
A permit authorizes the system’s design, installation, or repair with the county. An inspection evaluates whether an existing system is currently functioning and, in counties that require it, is often a separate step tied to selling the property.
Is a low well yield a dealbreaker when buying rural property?
Not automatically, but it matters more for larger properties, irrigation, or livestock. A yield test during your due diligence period tells you what the well can actually support, which should factor directly into your offer and your plans for the property.
If you’re looking at land, a cabin, or a ranch in Custer County and want a straight read on what the well and septic situation actually looks like before you write an offer, I’m happy to walk through it with you. Reach out anytime and we’ll go through the specifics together.
About Kayla Brady
Kayla Brady is a Realtor with HomeSmart Preferred Realty serving Westcliffe and Custer County, Colorado. She works with buyers and sellers across the Wet Mountain Valley on land, cabins, mountain and horse properties, ranches, and in-town homes, and has walked local clients through the well, septic, and water rights questions that come up in nearly every rural transaction.