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Septic Services in Cheyenne, WY

Laramie County County · Pop. 65,132

Cheyenne, Wyoming's state capital and largest city, sits at over 6,000 feet on the High Plains near the Colorado border. While the city core is served by municipal sewer, surrounding Laramie County features many acreage properties, small ranches, and rural residential developments that rely on onsite septic systems. The county's High Plains soils — predominantly loams with good percolation — are more accommodating than much of Wyoming's mountain terrain, but localized Pierre Shale formations with Bentonite clays create unpredictable expansive soil conditions. The constant high-wind environment is unique to Cheyenne and influences how evapotranspiration systems perform.

Septic Providers in Cheyenne (9)

Services in Cheyenne

Drain Field Repair

$2,000 – $15,000

Grease Trap Pumping

$200 – $800

Septic Inspection

$300 – $600

Septic System Installation

$3,500 – $20,000

Septic Tank Pumping

$275 – $600

Septic Repair

$500 – $5,000

Well Drilling

$6,000 – $25,000

Well Pump Repair

$300 – $3,000

Well Water Testing

$50 – $500

Well Water Treatment

$500 – $8,000

Septic Service Costs in Cheyenne

Service Average Cost
Septic Tank Pumping $225 - $400
Septic System Installation $8,000 - $20,000

Soil Conditions

Featherlegs loam and Altvan loam on the High Plains surface — Aridic Argiustolls and Typic Haplustalfs with moderate percolation; Nunn clay loam in lower positions with slower drainage; Larim gravelly sandy loam on upland ridges with excellent percolation; Bentonite-bearing Pierre Shale formations create localized expansive clay hazards

Featherlegs loam (Aridic Argiustoll) is the dominant septic-suitable soil in Laramie County — a well-developed argillic horizon over permeable subsoils with percolation rates of 25 to 60 minutes per inch. Larim gravelly sandy loam on ridges perc at 5 to 20 minutes per inch — excellent for conventional systems. Pierre Shale-derived soils including Nunn clay loam and associated Bentonite seams have percolation rates exceeding 90 minutes per inch with severe shrink-swell activity, requiring engineered systems.

Water Table: 20 to 50 feet in most areas; deeper in the High Plains; shallower near Crow Creek and Dry Creek drainages

Local Regulations

Laramie County Planning and WDEQ Water Quality Division jointly oversee Chapter 25 compliance. Properties within the watershed of Granite Reservoir (Cheyenne's water supply) face enhanced setback requirements and may require advanced treatment. The county encourages sewer extension over septic installation in denser subdivisions. WDEQ Registered Wastewater Installer credential required for all work.

Laramie County Planning and Development Issues septic permits in coordination with WDEQ. Cheyenne city proper is served by Cheyenne Board of Public Utilities sewer. Unincorporated Laramie County residential areas require full WDEQ Chapter 25 compliance. Permit fees $400 to $700.

Frequently Asked Questions — Cheyenne

What parts of the Cheyenne area are on septic systems?
Cheyenne city limits are largely served by municipal sewer. Rural residential areas throughout Laramie County — including ranch lots along I-25, Fox Farm, Carpenter, and Burns communities — are on private septic systems. Many acreage developments within 10 miles of the city also use septic. Contact Laramie County Planning to verify sewer availability for any specific address.
What is Bentonite and why does it matter for septic systems in Cheyenne?
Bentonite is a highly expansive clay mineral derived from weathered volcanic ash, found in Wyoming's Pierre Shale formations. When wet, Bentonite swells dramatically — sometimes to 15 times its dry volume. This creates structural damage to rigid septic tanks and pipe connections, and essentially zero percolation for leach fields. If a soil evaluation finds Bentonite-bearing materials, an engineered alternative system (mound, drip irrigation) must be designed to avoid the restrictive zone.
How does Cheyenne's wind affect septic systems?
Cheyenne's persistent high winds (averaging 12-14 mph) benefit evapotranspiration-based systems by increasing surface moisture loss, but they also accelerate UV degradation of exposed plastic components like risers and distribution boxes. All above-grade components should be UV-resistant. Wind-driven soil erosion can also expose leach field piping if proper revegetation is not established after installation.
Are there septic restrictions near Cheyenne's Granite Reservoir?
Granite Reservoir is a primary drinking water source for Cheyenne. WDEQ and Laramie County require enhanced setbacks and advanced treatment for any septic systems within the reservoir's contributing watershed. New systems are rarely approved in this area, and existing systems near the reservoir face increasing pressure to upgrade or connect to an extended sewer line.
What does a WDEQ Chapter 25 site evaluation involve?
A Wyoming Chapter 25 site evaluation includes a detailed soil profile description to a minimum depth of 5 feet using a backhoe pit, a percolation test in the design leach field area, measurement of seasonal high water table, and documentation of any restrictive layers. The evaluation must be performed by a WDEQ Registered Site Evaluator or Professional Engineer. Results determine the system type, size, and setback requirements.

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