Longmont, Colorado Well Depth, Yield, and Cost

How deep are wells around Longmont?

How much water do wells make near Longmont?

Longmont well depth depends on the ground below the lot

The median reported well depth near Longmont is 30 feet. The middle half runs from 16 to 50 feet, so a bid based on the typical local depth may be reasonable for some sites. Still, the range is wide: the 90th-percentile depth is 158 feet, and the deepest record reaches 600 feet.

Most recorded wells are under 100 feet, while 8% fall between 100 and 300 feet and 5% extend from 300 to 600 feet. The aquifer designation matters. Records name an unnamed or fractured-bedrock aquifer for 1,328 wells, compared with 112 alluvial wells and 16 Quaternary Alluvium wells. Granite and gneiss can fracture irregularly, so nearby depth is a guide, not a promise.

What Longmont wells produce for a household

Among the 93 records that report pump yield, the median is 12.0 gallons per minute. The middle half is 10.0 to 15.0 gallons per minute. Forty-seven percent report 5 to 15 gallons per minute, and 46% report more than 15 gallons per minute. No reported well falls under 1 gallon per minute.

That is a strong result in the available records, but the sample is much smaller than the total permit count. Yield also depends on the test, pump setup, storage, and the well’s intended use. Ask for the well-completion report and pump test, not just a seller’s statement that the well “has water.” A domestic or household-use well still needs a suitable pump, pressure system, and storage arrangement.

Longmont water levels look shallow, but the trend is limited

Only 53 records report a static water level, so the water-level sample is limited. In those records, the median depth to water is 10 feet, with the middle half from 8 to 11 feet. That suggests many tested wells encountered relatively shallow standing water.

The available facts do not provide a water-level series by decade, so they cannot establish that the local water table is dropping or rising. Static level is also not the same as pumping level. A buyer should ask when the measurement was taken, whether the well had rested before testing, and how much the level changed while pumping. Casing and grout details matter as well, especially where shallow groundwater may be exposed to surface sources.

Longmont permit history shows current drilling activity

Colorado DWR permit records are the starting point for checking a well’s legal status, permitted use, construction report, and recorded depth. The Longmont search area includes permits issued as recently as 2025. Forty-six permits were issued in the 2020s, while the full record contains 1,626 permits.

The records identify Authorized (Pe, Pg) as the most active driller, with 534 entries. Marshall Drilling, listed as Marshall, James C, appears on 88, and Harry Young Drilling, listed as Young, Harry J, appears on 17. These names describe the permit history; they are not a substitute for inspecting the well or confirming who is available for new work. Check the permit number, use type, construction report, and any change-of-use requirements before relying on the water right.

A Longmont well can cost more than the hole itself

Local drilling is modeled as fractured mountain bedrock, including granite and gneiss, at about $65 to $100 per foot. At the 30-foot median depth, the drilled hole works out to about $2,000 to $3,000. That is only the drilling portion, not the complete water system.

A finished well with pump, pressure tank, trenching, and electrical is estimated at $8,000 to $15,000 at the median depth. A deeper hole, difficult access, casing or grout requirements, and site-specific electrical or trench work can change the bid. Ask the driller to separate footage, casing, grout, development, pump equipment, pressure system, trenching, electrical, testing, and permit-related work so competing bids can be compared fairly.

Environmental, septic, and dry-hole checks near Longmont

Mapped environmental records within about 10 miles include 568 PFAS sampling or contamination sites, 41 historic mine features, and 8 EPA Superfund or cleanup sites. A mapped site does not automatically mean a particular parcel’s well is contaminated, but it is a reason to review the site history and test existing water. Ask for current laboratory results covering the concerns identified for the property.

Low yield is not the only risk. A fractured-bedrock well can miss a productive fracture or require more depth than nearby records suggest. Septic setbacks, soil conditions, well location, access for a rig, and space for a replacement system should be checked before building. If the basin is over-appropriated, an augmentation plan or other water-right requirements may affect new household use.

What to verify before buying a Longmont-area lot

Start with the DWR file for the exact parcel or home. Confirm the permit, permitted use, construction report, total depth, pump yield, static level, casing and grout, and the current pump and pressure equipment. The use mix in the records includes 33% domestic or household, 4% stock, 4% irrigation, and 43% monitoring, so the nearest permit may not be comparable to a home well.

For a vacant lot, obtain a written drilling and complete-system estimate and confirm where a rig, driveway, septic system, and electrical service can fit. For an existing home, make the sale contingent on water-quality and flow testing, inspection of the wellhead and pressure system, and review of repair history. Compare several nearby wells, including records around Niwot, Gunbarrel, and Mead, while treating every result as site-specific.

Well permits by decade near Longmont

What a new well costs in Longmont, CO

How this is built: the median permitted depth here times the per-foot range for this ground, plus the normal system costs. A lot at the 75th-percentile depth (50 ft) would run roughly $9,250–$17,000. See the full Colorado well cost guide.

Environmental sites mapped within about 10 miles

Counts come from EPA, USGS and state datasets layered on the Colorado Well Finder map. A count is not a verdict on any one well; it tells you what to test for.

Buying land near Longmont? Know what it costs to build before you buy the dirt.

A listing photo can't tell you whether a lot is a dream or a money pit. Two parcels near Longmont can carry the same asking price while one needs an $80,000 driveway and a $45,000 engineered septic the other doesn't. The well numbers on this page are the start of that answer. A Tri-Lakes Site Feasibility Report is the rest of it: a licensed general contractor, excavator and septic installer reads the parcel the way we would if we were about to build on it, and puts the real cost in writing before your money is committed.

Spend a little to know. Or gamble a lot to guess. Realtors sell the view and inspectors look at houses that already exist. We're the people who'd build it, so we catch what quietly turns a "great deal" into a budget disaster: bad access, buried rock, steep grade, soil that won't pass for a normal septic, water that's a fortune to reach. And if the lot is good, you've already got a builder ready to do the work, driveway to drywall.

• Instant Online Report, $99 — type the address and get a buildability read on the spot: parcel, terrain and slope, soil and septic outlook. Cheap enough to run on every lot you're shopping.
• Desktop Report, $500 — a contractor's from-the-desk feasibility read: Regulation 43 and county code, GIS parcel data, terrain, flood and drainage, soil and septic viability, setbacks and buildable envelope, nearby well depths from our 591,000-well database, the likely driveway route, and a preliminary site-development cost breakdown.
• On-Site Report, $2,000 — everything above, then boots and a drone on the actual ground: house pad and septic zone located, access and winter conditions checked, rock and soil observed in person, a 15 to 20 page written opinion you can hand a lender or seller. Credited toward your project if you build with us.

Under contract, comparing parcels, or a realtor with a rural listing whose buyers keep asking "what will it cost to build here?" This is the due-diligence step almost everyone skips, and the one that saves the most.

Common questions about wells in Longmont

Keep researching

More in Boulder County

All wells in Boulder County — county-wide depth, yield and cost figures.

Nearby areas