What does a septic system cost in Colorado?
Two neighbors can pay very different prices for a septic system. Here is why, and how to find out which side of the range you are on.
There is no single price for a septic system, because the system is designed for one specific piece of ground. What you pay depends on what your lot allows.
Most installs start around $15,000. The final price comes after a site visit, because soil, system type, home size and access set it. The county permit, soil test and design are extra and quoted separately, so your total may vary.
Soil is the biggest factor
A septic system cleans wastewater by letting it soak through soil. Soil that drains at a steady rate can use a simple gravity system. Soil that drains too slowly, such as heavy clay, needs a larger field or a pump to spread the water out. Soil that is too shallow over rock or groundwater may need the field built up above the ground.
You find out by having the soil evaluated. Colorado requires this before a system can be designed, so it is not an optional extra.
The system type follows the soil
- Gravity systems have the fewest parts and cost the least.
- Pressure-dosed systems add a pump and controls.
- Mound systems add imported sand and more earthwork.
- Engineered systems with a treatment unit add equipment and usually ongoing service.
We explain each type on the septic installation page.
Home size sets the system size
Systems are sized by the number of bedrooms, not bathrooms. More bedrooms means a larger tank and a larger field. If you plan to add a bedroom later, say so before the design is done.
Access changes the labor
An open, flat lot on the plains is quick to dig. A steep mountain lot with trees, rock and a narrow driveway takes smaller equipment and more time. The same system can cost more to build in Evergreen than in Bennett for that reason alone.
What is quoted separately
Three costs sit outside the installation price: the county permit, the soil test and the design. Each one depends on your county and your lot. Ask every company you talk to whether their number includes them, so you are comparing the same thing.
How to get a real number
Get a site visit and a written price. Then, if you want to check it, get a second one. If you bring us a written quote for the same job, we will beat it. Call or text (720) 273-0109.