Average Cost Range for a Perc Test
The average cost range for a perc test is $875 when two holes are dug for testing soil absorption rate for the approval, location and design of a septic system.
Tests range from a shallow hand-dug test to a deep hole percolation test requiring an excavator and operator. As a result, cost varies for all options from around $525 to $1,700. Itemized pricing for different test options is below.
Generally, complex soils that contain clay require more soil analysis, so the higher the cost of the test. The cost of a perc test does not include the design of the septic system, though many septic system companies are more than happy to handle a perc text for you as well.
Overview of Soil Perc Testing
A perc test, aka percolation test or perk test, is required in order to install a new septic system or replace an older septic system. The test determines whether soils are suitable for leach field installation, aka on-site sewage treatment, and if so, whether a conventional system or an engineered mound system is necessary. Types of septic systems installed vary by region of the country.
There are two types of tests considered perc tests. A traditional perc test involves digging at least two holes each two to three feet deep. Water is added to them to measure the rate of water absorption into the soil. This test might be enough if soils throughout your area are shown test after test to be sandy and fast draining.
An additional test, and one now required by most local health departments, is a deep hole test needed to visually examine the soil layers. Staining in the soil shows how high the water table is. A high-water table usually indicates the need for a raised mound drain field. If impermeable soil layers are present such as hardpan, rock or exceptionally heavy clay are present, they also mean an engineered system is required. Deep hole tests are dug by an excavator or a contractor with an auger at a higher cost.
Percolation Test Cost Factors
Whether your costs are more or less than $1,000 will depend on test type, soil conditions and local requirements.
Test Type – Deep hole tests using an excavator and operator are now standard except where soils throughout the region are sandy and drain very well.
Number of Test Pits – Two pits are standard, but if they yield different soil conditions and additional pits are dug for verification, the cost will be higher. On large parcels, as many as 6 or 8 pits might be dug at the homeowner’s request in order to give them more building location options.
Soil Analysis – When a soil scientist is used in the process, fees will be higher than average.
Testing by a Licensed Engineer – In many areas, tests can be completed by septic system installers or excavators who have been cleared by local officials for the work. But if an engineer is required to conduct the test, cost is several hundred dollars higher.
Access – Heavy brush, wet areas at the road or steep slopes that make access difficult increase the time a test takes – and raises the price.
Soil Conditions – Wet springtime soils, rocky soils or heavy clay soils require more time to test, and cost is higher.
Travel Time – If your property is located in a rural area some distance from “town,” then expect higher costs to cover time and transportation expenses.
Local Fees – The cost of permits and fees vary widely across the country. In heavily regulated areas, costs can be $200 to $500 higher than average.
Perc Testing Services and Costs
Here is pricing for common scenarios.
- Hand-dug Perc Hole Test & Analysis | $525 – $800
- Excavator-dug Perc Holes & Analysis | $675 – $1,100
- Licensed Engineer Fees | Add $200 to $500
- Soil Scientist Fees | Add $150 – $400
Hole type and the number of test pits dug are major cost factors.
- Two shallow holes | $525 – $800
- Two excavated pits | $675 – $1,100
- Additional shallow holes | $50 – $115 per hole
- Additional excavated pits | $125 – $200 per hole
- Difficult access | Add $100 to $400
- Wet or frozen conditions (If testing is possible) | Add $200 – $400
Permits, Inspection, and Labor Costs
Permits and Inspection
- $100 – $450 | The types and number of pits dug plus local regulations and fees determine permit cost.
Labor costs vary for the professionals who take part in the onsite test or soil analysis.
- Excavator with operator | Around $200 minimum plus up to $200 per additional hour. Excavators are typically onsite for an hour or less.
- Licensed engineer | $150 – $225 per hour
- Soil scientist | $250 – $500 per test
Time Required for a Perc Test and Report
- 2-3 Hours for Testing | The test itself usually takes an hour or two for two holes. Additional holes can be dug by an excavator at a rate of 2-3 per hour.
- 1 Day for Follow Up | A technician or engineer might return on the next day to examine the saturation of water into the soils.
- 3-21 Days for Report | Keep in mind that the time required from scheduling the test to having results returned can take 3-21 days and perhaps longer during busy times of the year when there is a wait list for services.
Having a perc test done is usually in conjunction with a new home build, new septic system or replacing an existing septic and leach field. The projects below are closely related to having a perc test.
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DIY or Hire a Pro
When planning to walk a property we are considering buying, we’ve occasionally asked the owner if we can dig a few shallow test holes to get a look at the underlying soils. We’ve never had a landowner object.
If you know what you’re looking for – what type of soils are present (clay, loam, sand, gravel) plus water staining indicating the seasonal water table – a DIY test can save time and money. Take a few gallons of water with you to pour into the hand-dug holes. If the water readily drains (sand/gravel soils), it’s a good indication the soils are suitable for a system. If it doesn’t (heavy clay), look for another property or consider professional perc testing. Also, if water pools in the hole from below or the sides before you pour any in, that’s not a good sign.
Keep in mind that DIY tests won’t satisfy local officials. Perc testing and soil analysis have to be performed by pros the health department has certified for the work. In other words, you’re going to spend $525 to $1,700 for a certified test.
Note on cost: A lot of sites posts costs starting under $250. Those prices simply aren’t realistic. We post some of them below for comparison, but the low-end prices in that range are not accurate.
Compare Costs from Leading Resources
- HomeAdvisor: $750 - $1,850, Perc Test & Analysis
- Building Advisor: $300 - $1,200, Perc Test - No Analysis
- Upgraded Home: $700 - $1,750, Perc Test & Analysis
- Retipster: $150 - $1,500, Test or Test + Analysis
- Cost Helper: $100 - $1,000, Test Only
- Fixr: $600 - $800, Low-end Test & Analysis
Common Questions and Answers
When is a perc test done?
Whenever a septic system is required or needs to be replaced. Common times are when building on land and no municipal sewer system is available or when an old septic system fails and must be replaced.
Who does a perc test?
In a typical scenario, a local excavator or septic system company meets an official from the health department at the property. Holes are dug, and the official conducts the test. If soils are gathered for analysis, a soil scientist will handle that part of the test.
What are the best soils for a perc test?
Sand or gravel, sandy loam and some loam soils.
What are the worst soils for a perc test?
Clay and clay loam.
How long are perc test results good for?
Three Oaks Engineering says, "An Improvement Permit/Construction Authorization issued by a Local Health Department is valid for 5 years. An evaluation by a Licensed Soil Scientist does not expire; the results will generally stay the same so long as the area evaluated does not physically change."
What if the perc test fails?
It might mean the property isn’t buildable, most often because of a high water table that makes the soils unstable. However, some perc tests fail for a conventional septic system but show that soils are OK for a raised mound engineered system.
Can a percolation test be done in winter?
If there’s no frost in the ground, then yes. Even where light freezing is present, a backhoe can usually get through it. If the soil is in a “deep freeze,” a test might be impossible.
My health department says we have do a perc test in the spring, not in summer. Why?
Where soils are known to be "iffy" and there is a high seasonal water table, officials might want to do the perc test under "worst case" conditions, which are usually spring when heavy rains and melting snow create wet soils.