Do I need a permit to build or replace a septic system on the Front Range?

Yes. Colorado delegates septic permitting to county public health agencies, so a new or replacement system needs a construction permit from the county before work starts. Jefferson County Public Health publishes its permit fees, and the Jefferson, Larimer, and Boulder county health departments each publish the OWTS regulations that govern design, siting, and installation.

How much does a new septic system cost in Colorado?

Published contractor figures put most Colorado projects between $10,000 and $50,000 or more. Tri-Lakes Contracting, a Tri-Lakes-area contractor, lists conventional systems at $10,000 to $20,000 and pressure distribution at $15,000 to $25,000, with engineered and advanced-treatment systems above those ranges. Soil conditions, lot access, and county requirements decide where a specific quote lands.

Will a new system make my next home sale easier?

For a window of time, yes. Boulder County exempts a sale when the entire system received final county approval less than five years before closing, and Larimer County makes an exception when final approval came less than three years before the request. Jefferson County requires its use permit only for systems installed more than five years before the sale date, per each county's published program materials.

Who actually designs and installs the system?

Independent local professionals you hire. A site and soil evaluation comes first, then a design that fits the county OWTS regulation, then the construction permit, the build, and county inspection. We are a matching service, not a contractor, so every step is performed by the independent local septic professional you choose, and the decision on who to hire is always yours.

New systems and full replacements

OWTS installation and permits on the Front Range

A failing septic system hands a Jefferson County or Larimer County homeowner two projects at once: the physical build, and the county permit file that makes the build legal. The two are inseparable. The permit decides what can be built, the soil decides what must be built, and the paperwork you keep at the end decides how smoothly your next home sale goes.

This page covers who issues the permit in each county, what a new on-site wastewater treatment system (OWTS) project involves, and the published Colorado cost figures that exist, labeled by who published them. When you are ready for quotes, we connect you free with an independent local septic contractor.

The permit comes from your county, not the state

Colorado's On-site Wastewater Treatment Systems Act (C.R.S. 25-10-101 and following) and Water Quality Control Commission Regulation 43 (5 CCR 1002-43) delegate the permitting of septic systems of 2,000 gallons per day or less to county public health agencies, and each county's local OWTS regulation must be at least as stringent as Regulation 43. The statewide program sits with the Colorado Department of Public Health and Environment, but the office that reviews your application, inspects your build, and signs the final approval is your county health department.

Jefferson County publishes construction permit fees we can cite directly. Per the Jefferson County Public Health FAQ, an OWTS construction permit runs $1,023 for a new system, repair, or addition, $523 for a tank replacement only, and $250 for a renewal. Two cautions: these are construction permit fees, not the use permit issued at a home sale, and fee schedules change, so confirm the current figure with the department. Jefferson County Public Health's Environmental Health Services office is in the Courts and Administration Building at 100 Jefferson County Parkway, Suite 4500, in Golden, per the department's About Us page.

The county rulebooks themselves are public. If you want the primary sources your designer and installer must satisfy, they are the Jefferson County OWTS Regulations (2018), the Larimer County OWTS Regulations (2024), and the Boulder County OWTS Regulations.

How a replacement project actually runs

The sequence is broadly the same in all three counties, because all three regulations descend from Regulation 43. What differs is the local detail, which is why the contractor you hire should work in your county regularly.

Site and soil evaluation. The soil on your lot determines what kind of soil treatment area can be built, and whether a conventional design is even an option. Foothills lots with shallow rock and plains lots with tight clay pull in different directions.
Design. A system design matched to the soil findings, the home's wastewater flow, and the county OWTS regulation.
Construction permit. The application goes to the county public health agency, which reviews the design before any digging starts.
The build. Tank, distribution, and soil treatment area go in under the permit.
County inspection and final approval. The county checks the work and signs off. Keep every page of this file. The dates in it are what the transfer exemption windows below are measured from.

Not every failed inspection ends in a full replacement. Sometimes the fix is a component: a distribution box, a line, a tank. The septic repair page covers that middle ground, and a proper septic inspection is how you find out which side of the line your system is on.

What a new system costs in Colorado

A full OWTS is a five-figure project, and the honest answer to "how much" is a range that depends on soil, design type, and access. The most detailed published Colorado figures we can cite are contractor-published, meaning one firm's cost guide rather than a government fee schedule. Per the Tri-Lakes Contracting cost guide (a Tri-Lakes-area contractor), Colorado quotes commonly run $10,000 to $50,000 or more: conventional systems at $10,000 to $20,000, pressure distribution at $15,000 to $25,000, and engineered or advanced-treatment systems well above that.

For one specific design type in the Denver area, Affordable Septic Pumping (contractor-published, Denver) puts an aerobic septic system at $10,000 to $20,000.

Treat all of these as orientation, not a bid. The number that matters is a written quote for your lot from an installer who has seen your soil report, and comparing two or three of those is worth the scheduling hassle. We can connect you with an independent local contractor to start that process, free, and here is how we get paid for it.

A new system resets the transfer clock

Each Front Range county ties its transfer document to the age or approval date of the system, so a documented new install pays off again when the house sells. Jefferson County requires its use permit only when the system was installed more than five years before the sale date, per the Use Permit Program. Larimer County makes an exception when the system received final approval less than three years before the request, per the county's Transfer of Title program. Boulder County exempts the sale when the entire system received final county approval less than five years before closing, per the county's certification instructions (PDF).

Outside those windows, the sale runs through the county process like any other. The transfer guide walks all three counties step by step.

The transfer inspection, explained Read the transfer guide

Where new systems go in

The replacement market lives where the sewer lines stop. In Jefferson County that means the foothills around Golden, the unincorporated pockets beyond Arvada's city utility, and the mountain subdivisions around Evergreen. Evergreen's history is a case study in why this page exists: the Evergreen Sanitation District was created in 1948 to solve the problem of failing individual septic systems, and today the Evergreen Metropolitan District treats wastewater for the Evergreen Metro, West Jefferson, and Kittredge districts, while homes outside those service areas remain on OWTS regulated by Jefferson County Public Health, per the district's own history. Systems age, and the ones outside the district lines get replaced one lot at a time.

In Larimer County, the work concentrates in the on-septic ring around Fort Collins and Loveland. The county's 2024 OWTS regulations, linked above, are the rulebook a new design must satisfy, and the Larimer County Department of Health and Environment reviews the file.

In Boulder County, the question a replacement answers is usually the Property Transfer Certificate: a system that cannot pass the transfer inspection either gets repaired or replaced before closing, or the buyer takes the work on under a repair agreement. The Boulder page covers the certificate specifics.

Get quotes from an independent local installer

Tell us the county, what the system is doing, and anything you know about its age or design. We connect you free with an independent local septic contractor for the evaluation, the design conversation, and the quote. You pay the contractor directly, and the decision on who to hire stays yours.

Comparing options first? See all services, including routine pumping that stretches the life of the system you already have.

Questions homeowners ask

Do I need a permit to build or replace a septic system on the Front Range?: Yes. Colorado delegates septic permitting to county public health agencies, so a new or replacement system needs a construction permit from the county before work starts. Jefferson County Public Health publishes its permit fees, and the Jefferson, Larimer, and Boulder county health departments each publish the OWTS regulations that govern design, siting, and installation.
How much does a new septic system cost in Colorado?: Published contractor figures put most Colorado projects between $10,000 and $50,000 or more. Tri-Lakes Contracting, a Tri-Lakes-area contractor, lists conventional systems at $10,000 to $20,000 and pressure distribution at $15,000 to $25,000, with engineered and advanced-treatment systems above those ranges. Soil conditions, lot access, and county requirements decide where a specific quote lands.
Will a new system make my next home sale easier?: For a window of time, yes. Boulder County exempts a sale when the entire system received final county approval less than five years before closing, and Larimer County makes an exception when final approval came less than three years before the request. Jefferson County requires its use permit only for systems installed more than five years before the sale date, per each county's published program materials.
Who actually designs and installs the system?: Independent local professionals you hire. A site and soil evaluation comes first, then a design that fits the county OWTS regulation, then the construction permit, the build, and county inspection. We are a matching service, not a contractor, so every step is performed by the independent local septic professional you choose, and the decision on who to hire is always yours.