What Property Owners Need to Know About Soil Testing & Septic Systems Costs and changes in the Colorado regulation 43 and its updates
- Ern Dog
- 3 hours ago
- 6 min read
If you own property in Colorado or plan to build, buy land, or upgrade a septic system, you need to understand the recent changes in Regulation 43. These updates, effective June 15, 2025, introduce new statewide rules that every county must meet or exceed by June 15, 2026. The key message is clear: soil testing is now mandatory and forms the foundation of any compliant septic system. This post breaks down what these changes mean for you, how soil testing affects your septic system costs, and what steps you should take to stay compliant.

What You Should Know About Colorado Regulation 43
Regulation 43 governs On-Site Wastewater Treatment Systems (OWTS), commonly called septic systems, across Colorado. It sets the minimum standards for how these systems are designed, installed, and maintained. Counties can enforce stricter rules, but they cannot go below the state’s baseline.
The 2025–2026 updates focus on improving system reliability, protecting the environment, and ensuring long-term maintenance. Here are the most important changes:
Mandatory soil evaluations with at least two test pits before designing a system
Detailed design documentation including elevations, flow calculations, and setback distances
Stricter oversight for advanced treatment systems to ensure proper function
New maintenance and inspection rules for higher-level septic systems
Phasing out outdated systems such as cesspools, requiring full upgrades
These changes mean septic systems must be designed based on actual site conditions, not assumptions or incomplete data.
Why Soil Testing Is More Important Than Ever
Soil testing is no longer optional under the updated Regulation 43. It is a required part of the site evaluation process before you can design or permit a septic system.
Counties now require:
At least two soil test pits dug to evaluate soil conditions
Assessment down to limiting layers or groundwater to understand drainage and absorption
Analysis of soil type, structure, and permeability to determine system suitability
This detailed soil data helps engineers design septic systems that work efficiently and protect groundwater.
Understanding Septic System Costs Under the New Rules
The updated Regulation 43 may increase overall septic system costs, but these expenses protect your property and the environment. Here’s a breakdown of typical costs you might face:
Soil testing and site evaluation:Â $500 to $1,500 depending on milage
System design and engineering:Â $975 to $3,000
Septic system installation:Â $6,500 to $20,000 or more depending on system type and soil conditions
Permitting fees:Â Vary by county, usually a few hundred dollars to $1500
Ongoing maintenance and inspections:Â $200 to $500 annually for advanced systems
How Soil Testing Affects Your Septic System Costs
Soil testing adds upfront costs but can save you money in the long run by preventing system failures and costly repairs. Here’s how it impacts your expenses:
Initial testing fees vary but typically range from $500 to $1,500 depending on site complexity
Design costs may increase because engineers use detailed soil data to create customized systems
Potential for higher installation costs if soil conditions require advanced treatment or larger drain fields
Reduced risk of future repair costs by avoiding unsuitable system designs
For example, if your soil has a high water table or poor drainage, the system may need additional components or a larger absorption area, increasing installation costs. Without testing, you risk installing a system that fails early, leading to expensive fixes.

What the Changes Mean for Property Owners
You must now provide verified soil data before you can get a septic system permit. This affects you whether you are:
Building a new home or structure
Buying undeveloped land
Upgrading or replacing an existing septic system
Here are practical steps to take:
Schedule soil testing early in your planning process to avoid delays
Work with certified professionals who understand the new Regulation 43 requirements
Review your soil test report carefully to understand any limitations or special design needs
Budget for potential higher costs if your soil conditions require advanced systems
Stay informed about your county’s specific rules, as some may have stricter standards
Counties must adopt equal or stricter standards by June 15, 2026, so local rules could become more demanding.
How to Prepare for the New Regulation 43 Requirements
To comply with the updated rules and manage costs effectively, consider these tips:
Hire a qualified soil scientist or engineer to perform soil evaluations and interpret results
Request multiple test pits to get a comprehensive view of your site’s soil profile
Ask about limiting layers and groundwater levels that affect system design
Plan for additional inspections and maintenance if you install an advanced treatment system
Keep detailed records of soil tests and system designs for future reference
Being proactive helps you avoid surprises and ensures your septic system meets all legal and environmental standards.

While these costs may seem high, they reduce the risk of system failure, contamination, and costly repairs. Investing in proper soil testing and compliant system design is a smart choice for long-term savings.

Final Thoughts on Regulation 43 and Soil Testing in Colorado
The changes to Colorado’s Regulation 43 make soil testing a critical step for anyone dealing with septic systems. These updates ensure systems are designed for real site conditions, improving performance and protecting water quality.
As a property owner, you should:
Prioritize soil testing early in your project
Understand how soil conditions affect system design and costs
Work with professionals familiar with the new rules
Stay updated on your county’s specific requirements
Taking these steps will help you navigate the new regulations smoothly and avoid costly mistakes. Your septic system is an important investment—make sure it’s built on a solid foundation.
Here are some helpful links to each counties health department.
What Property Owners Need to Know About Soil Testing & Septic Systems Costs and changes in the Colorado regulation 43 and its updates: a Breakdown by links and counties
Colorado County Septic System (OWTS) Links
Use the links below to access official county septic regulations, permits, and requirements.
Front Range & Metro Area
Adams County – https://adcogov.org/onsite-wastewater-treatment-systems
Arapahoe County – https://www.arapahoegov.com
Boulder County – https://bouldercounty.gov/environment/water/individual-sewage-disposal-systems/
Broomfield County – https://www.broomfield.org
Denver County – https://www.denvergov.org
Douglas County – https://www.douglas.co.us/health-department/septic-systems/
Jefferson County – https://www.jeffco.us/1422/Onsite-Wastewater-Treatment-Systems
Northern Colorado
Larimer County – https://www.larimer.gov/health/environmental-health/septic-systems
Weld County – https://www.weldgov.com
Logan County – https://www.logancountyco.gov
Morgan County – https://www.morgancounty.colorado.gov
Sedgwick County – https://www.sedgwickcountyco.gov
Phillips County – https://www.phillipscounty.colorado.gov
Washington County – https://www.co.washington.co.us
Yuma County – https://www.yumacounty.net
Pikes Peak Region
El Paso County – https://admin.elpasoco.com/public-health/environmental-health/septic-systems/
Teller County – https://www.co.teller.co.us
Mountain & Central Colorado
Clear Creek County – https://www.co.clear-creek.co.us/610/Onsite-Wastewater-Treatment-Systems
Gilpin County – https://gilpincounty.colorado.gov
Summit County – https://www.summitcountyco.gov
Park County – https://www.parkco.us
Lake County – https://www.lakecountyco.com
Chaffee County – https://www.chaffeecounty.org
Eagle County – https://www.eaglecounty.us
Pitkin County – https://pitkincounty.com
Garfield County – https://www.garfield-county.com
Routt County – https://www.co.routt.co.us
Grand County – https://www.co.grand.co.us
Jackson County – https://jacksoncountyco.gov
Western Slope
Mesa County – https://health.mesacounty.us
Delta County – https://www.deltacountyco.gov
Montrose County – https://www.montrosecounty.net
Ouray County – https://www.ouraycountyco.gov
San Miguel County – https://www.sanmiguelcountyco.gov/499/On-Site-Wastewater-Treatment-Systems
Gunnison County – https://www.gunnisoncounty.org
Hinsdale County – https://www.hinsdalecountycolorado.us
Southwest Colorado
La Plata County – https://www.co.laplata.co.us
Montezuma County – https://montezumacounty.org
Dolores County – https://www.dolorescounty.org
Archuleta County – https://www.archuletacounty.org
San Juan County – https://sanjuancounty.colorado.gov
San Luis Valley
Alamosa County – https://www.alamosacounty.org
Conejos County – https://www.conejoscounty.colorado.gov
Costilla County – https://costillacounty.colorado.gov
Rio Grande County – https://riograndecounty.org
Saguache County – https://www.saguachecounty.colorado.gov
Mineral County – https://www.mineralcountycolorado.com/land-use-office/page/site-wastewater-treatment-system-owts
Eastern Plains
Elbert County – https://www.elbertcounty-co.gov/341/Onsite-Wastewater-Treatment-Systems-OWTS
Lincoln County – https://www.lincolncountyco.us
Kit Carson County – https://kitcarsoncounty.org
Cheyenne County – https://www.co.cheyenne.co.us
Kiowa County – https://www.kiowacountycolorado.com
Crowley County – https://www.crowleycountyco.gov
Otero County – https://www.oterogov.org
Bent County – https://www.bentcounty.net
Prowers County – https://www.prowerscounty.net
Baca County – https://www.bacacountyco.gov
Multi-County Health Departments
Some counties fall under regional health agencies:
Tri-County Health Department – https://www.tchd.org
Northeast Colorado Health Department – https://www.nchd.org
Southeast Health Group – https://www.sehd.org
San Juan Basin Public Health – https://sjbpublichealth.org
Keywords This Page Targets
Colorado septic system regulations Colorado OWTS requirements Septic permits Colorado by county Soil testing for septic Colorado Colorado Regulation 43 septic Septic system cost Colorado County septic requirements Colorado Onsite wastewater treatment systems Colorado
Final Thoughts
Navigating septic regulations in Colorado can be complex—but starting with the right county resources makes all the difference.
Before building or buying land:
Check your county regulations
Complete soil testing ( Preferably by Land systems West!)
Budget for system costs ( Your itemized quote comes with soil test results.)
Work with experienced professionals
At Soil Test and Septic, we help property owners across Colorado simplify the process—from soil evaluations to full system design—so you can move forward with confidence.
