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Septic Services in Billings, MT

Yellowstone County County · Pop. 117,116

Billings is Montana's largest city, situated in the Yellowstone River valley beneath the distinctive rimrock sandstone cliffs that define the city's skyline. As the commercial and medical hub of the northern Great Plains, Billings has a well-developed municipal sewer system, but Yellowstone County's surrounding unincorporated communities—Lockwood east of the city, the Heights above the rimrocks, and rural areas across the county—have a substantial onsite septic system inventory. The dominant soil challenge in the Billings area is Bearpaw shale, a marine sedimentary formation that outcrops on hillsides and underlies shallow soils on the county's benchlands. Midway and related clay soils developed over Bearpaw shale have extremely poor permeability. In contrast, Yellowstone River terrace soils (Younglove, Hanly series) offer better drainage but are subject to floodplain constraints. Billings' semi-arid climate limits soil biological activity, but the Yellowstone River corridor's ecological sensitivity requires careful system siting to protect one of Montana's most important rivers.

Services in Billings

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Drain Field Repair

Restore or replace failed leach fields and drain lines to prevent sewage surfacing and groundwater contamination.

$2,000 – $15,000

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Grease Trap Pumping

Commercial grease trap cleaning and pumping to prevent sewer blockages and maintain health code compliance.

$200 – $800

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Septic Inspection

Comprehensive evaluation of your septic system's condition, required for real estate transactions in most states.

$300 – $600

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Septic System Installation

Complete new septic system design and installation, from perc testing to final inspection.

$3,500 – $20,000

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Septic Tank Pumping

Regular pumping removes accumulated solids from your septic tank, preventing backups and extending system life.

$275 – $600

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Septic Repair

Diagnose and fix septic system problems including leaks, clogs, baffle failures, and component replacements.

$500 – $5,000

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Well Drilling

Professional water well drilling for residential and commercial properties without access to municipal water.

$6,000 – $25,000

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Well Pump Repair

Diagnose and repair well pump failures, pressure tank issues, and water flow problems.

$300 – $3,000

Septic Providers in Billings (7)

Septic Service Costs in Billings

Service Average Cost
Septic Tank Pumping $175 - $325
Septic System Installation $6,500 - $18,000

Soil Conditions

Billings area soils are dominated by the Midway-Vananda complex on upland terraces—Midway clay is a shallow soil over Bearpaw shale, an expansive marine shale with very high montmorillonite clay content. Arle channery clay loam and Heldt clay are also found on benchland areas. Yellowstone River floodplain soils include Younglove silt loam and Hanly loamy fine sand—moderately permeable alluvial soils. Benchlands south of Billings have Hesper and Crago gravelly loam series with moderate permeability.

Midway clay (USDA series) is a shallow Torriorthent developed in residual Bearpaw shale material. Its parent material has virtually zero hydraulic conductivity, making any in-ground absorption system non-functional. On Midway clay sites, engineered mound systems using imported permeable fill are required. Vananda clay loam is a related series with similar limitations. Younglove silt loam on Yellowstone River terraces is a deep alluvial Mollisol with moderate permeability (30-60 min/inch), suitable for conventional pressure distribution systems where groundwater separation is adequate.

Water Table: Yellowstone County benchland and upland areas show groundwater at 15 to 50 feet. Yellowstone River floodplain areas have seasonal groundwater at 4 to 12 feet. Spring snowmelt and Yellowstone River flood events can temporarily raise floodplain groundwater to within 1 to 3 feet of surface.

Local Regulations

Yellowstone County Environmental Health administers Montana DEQ ARM 17.36 permits. Bearpaw shale areas require engineered mound or alternative system designs. Yellowstone River setback requirements apply to floodplain-adjacent properties. All systems require PE or licensed soil scientist evaluation per Circular DEQ-4. DEQ's subdivision sanitation review (Circular DEQ-4) governs new lot creation. Frost depth design minimum is 42 inches.

Yellowstone County Environmental Health administers SWTS permits under Montana DEQ ARM 17.36 and Circular DEQ-4. Billings proper has municipal sewer service through the City of Billings. Unincorporated Yellowstone County including Lockwood, Laurel outskirts, Broadview, and rural acreages rely on septic systems. All new systems require PE or licensed soil scientist evaluation. DEQ approval is required for Sanitation in Subdivision projects.

Frequently Asked Questions — Billings

What is Bearpaw shale and why is it a challenge for Billings area septic systems?
Bearpaw shale is a Cretaceous marine sedimentary formation that underlies much of the Billings area benchlands. It contains extremely high montmorillonite clay content with essentially zero permeability. Soils derived from Bearpaw shale (Midway clay and related series) are impermeable to septic effluent, making conventional drainfields non-functional. Sites on these soils require engineered mound systems using imported permeable sand and gravel fill.
What is the Sanitation in Subdivision (SIS) review for Montana and does it affect Billings?
Montana DEQ's Circular DEQ-4 requires a Sanitation in Subdivision (SIS) review for any subdivision creating lots that will use onsite septic systems. In Yellowstone County, DEQ must approve the sanitary design for all new subdivisions, including confirming that adequate soil exists for the proposed system type. This means a licensed engineer must evaluate and certify soil conditions before a subdivision plat is approved by DEQ.
Does Billings' dry climate help or hurt septic system performance?
Billings' semi-arid climate (13.5 inches annual precipitation) means drainfields are not frequently hydraulically overloaded by rainfall, which is a modest benefit. However, low moisture limits soil biological community activity, reducing natural treatment capacity in the soil. The combination of dry conditions and Bearpaw shale-influenced soils means most Yellowstone County systems depend on mound or pressure distribution designs rather than native soil treatment.
What frost depth standards apply to septic systems in the Billings area?
Montana DEQ Circular DEQ-4 and Yellowstone County require septic system distribution pipes and other buried components to be installed below the 42-inch frost depth for the Billings area. Access risers must extend to grade level to allow inspection and pump-out during winter without excavation. Pump tanks and ATU components require thermal insulation if buried at shallow depth.
How often should I pump my septic tank near Billings?
Yellowstone County Environmental Health recommends pumping standard residential septic tanks every 3 to 5 years. Billings' semi-arid climate and cold winters moderately slow bacterial decomposition in tanks, so staying near the 3-year interval is advisable for homes with 3 or more bedrooms or garbage disposal use. Arrange pump-outs in fall before freeze-up or in spring after ground thaw.