Septic systems, called onsite wastewater treatment systems (OWTS) in Colorado, use a septic tank, and the natural properties of the soil to treat wastewater from homes and businesses not served by a sanitary sewer. Wastewater can come from a variety of sources, including your washing machine, sinks, showers, and of course, toilets. It can also come from auxillary buildings, such as garage restrooms, or “mother-in-law” apartments.
Before purchasing a property, you should ALWAYS check with your local Environmental Health Department to see if any records exist regarding the property's means of wastewater treatment. Many counties in Colorado have public databases of OWTS records than can tell you the size of the system and for how many bedrooms or occupants it is permitted. Note that this number may be different than the real estate listing!
Wastewater first exits a building into a septic tank, where solids and FOG (fats, oils, and grease) settle and remain in the tank to be pumped by a service professional periodically. The pre-treated wastewater then flows (using either gravity or a pump) out of the septic tank and into the soil treatment area (STA), sometimes called a leachfield, where it is dispersed and treated by the native, or imported, soil. The size of your STA will depend on the wastewater produced by the building and the type of soil beneath it.
Each system is unique, which can create dramatically different costs, even between neighboring properties. Common costs include permitting fees, engineering & design fees, and the cost of installation. For accurate permitting fees, check with your local Environmental Health Department. For engineering & design fees, give us a call to discuss your specific project needs and how we would price it. Given the material costs of septic tanks and other components, installation is by far the most expensive and variable cost in the process. In many cases, you will need a system design before receiving bids from installers. In-all, a single-family residential septic system can cost anywhere from $15,000 to over $60,000. You may want to get multiple bids before selecting an installer.
Every septic system installed in Colorado needs to be permitted. The State has developed a set of OWTS regulations, which sets the minimum standards for OWTS design. Each local Environmental Health Department can then expand upon those standards to address the specific environmental and public health risks of their communities. These standards include minimum setbacks from features such as wells and streams as well as requirements for individual OWTS components like septic tanks and system piping. Improper OWTS design, installation, or maintenance can have adverse impacts on a community and must be taken seriously on every project.
There are many service providers across Colorado that can inspect your system to determine if it is in need of repair. If you think your OWTS might be failing, please reach out to one of these companies first. Give us a call if you need referrals in your area. Some obvious signs of problems are an empty septic tank (if it hasn't been pumped recently), ponding or surfacing water around your soil treatment area, or backups into your building. While no system is guaranteed to last any amount of time, most modern septic systems installed today are expected to last 20-30 years or more.
OWTS design depends on the wastewater produced and the soil in the STA. Many areas of Colorado are characterized by soil that will not adequately treat wastewater using gravity alone. In these situations, a pump is required to improve distribution within the system. Improved distribution helps to ensure more even dispersal of wastewater in the STA, and therefore better treatment, protecting the groundwater beneath the STA from contamination. Pumps require an electrical connection but are otherwise a low-maintenance component in an OWTS.
Higher Level Treatment (often abbreviated as HLT), uses additional treatment installed in conjunction with a regular septic tank to treat the wastewater to cleaner levels prior to discharging it to the STA. HLT may be required on commercial properties that produce higher-strength wastewater or any property that may specific development challenges unique to the lot. Many properties, especially in more populous areas, are unable to meet the required setbacks from wells, creeks, streams, or other features. Using an HLT system allows for development of a septic system in a smaller area while maintaining a low environmental and public health risk.
Most counties in Colorado require a licensed installer; however, some will allow a homeowner to install their own system. You will need to contact your local Environmental Health Department for requirements in your area.