Septic & OWTS · Boulder County
Septic system installation in Boulder County, Colorado
Tri-Lakes designs, permits, and installs onsite wastewater systems throughout Boulder County — from Boulder to Ward. We build for steep foothill and canyon lots, decomposed granite, and wildfire-interface ground, and we handle the Boulder County Public Health permit and inspections start to finish.
Boulder County sits in the Front Range foothills at roughly 5,200–9,000 ft — ground that decides how a septic system has to be built.
Onsite wastewater on Boulder County lots means designing around steep foothill and canyon lots, decomposed granite, and wildfire-interface ground. Those conditions rule out a one-size drainfield: the soil evaluation drives whether your lot takes a conventional gravity system, a pressure-dosed field, or an engineered treatment unit. We've built all three across the Front Range foothills.
Every install is permitted through Boulder County Public Health under Colorado's Regulation 43. We prepare the stamped design, submit the OWTS permit, coordinate the county's inspections, and do the excavation in-house — so the same crew that reads your soil is the one setting your tank.
Towns we serve in Boulder County
- Boulder
- Longmont
- Nederland
- Lyons
- Ward
How your Boulder County project works, start to finish
Site Feasibility Report
We start at your lot. On a site visit we check property setbacks, read the slope, make a hands-on visual assessment of the soil, and cross-reference county and health-department code for anything that could constrain a system. You get a written feasibility report and a real plan for the site — typically within three business days.
Testing Proposal
With the feasibility done, we quote the next step — the soil profile testing — so you know the cost before going any further.
Soil Profile Pit Test
Once you move forward, we come back out and dig two soil profile pits to read the actual soil horizons on your lot. That's the hard data the design depends on — no guesswork, no assumptions.
Engineered System Design
We hand the soil data to a licensed engineer, who designs and stamps the septic system plans your county requires.
System Proposal
With stamped plans in hand, we price the materials and permitting off the design and give you a firm quote on the actual system.
Installation
Once the system is approved and paid, our crew installs it — tank, drainfield or treatment unit, and lines. The same crew that read your soil is the one setting your system.
Inspection & Final
We schedule the county's final inspection, backfill, restore the site, and hand you a system documented for the life of the property.
Septic in Boulder County — questions
Who permits a septic system in Boulder County?
Onsite wastewater permits in Boulder County are handled through Boulder County Public Health under Colorado's Regulation 43. We prepare the design and submit the OWTS permit, then coordinate the inspections for you.
Can you install septic on Boulder County's terrain?
Yes. Boulder County sits at roughly 5,200–9,000 ft with steep foothill and canyon lots, decomposed granite, and wildfire-interface ground. We design pressure-dosed, advanced-treatment, and engineered systems specifically for these conditions.
How much does a septic system cost here?
It comes down to your soil and the system type your lot requires. We start with a feasibility report and soil profile pits, then price the real system off the engineered plans — not a guess over the phone.
Septic work in the high country
Already have engineered septic or OWTS plans? Upload the PDF for an instant Colorado installation estimate, then have Tri-Lakes, a licensed Colorado OWTS installer, price and build the system.
Building or fixing a septic system in Boulder County?
Send your lot details and we'll map the soil test, design, Boulder County Public Health permit, and install.
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