Proper method for inspecting septic systems

Proper septic inspection method:

On April 16 2011 the State of New Hampshire change the rules and septic systems can no longer be repaired. If a septic system goes into failure a complete new system must be designed, installed by a licensed contractor and approved by the State of New Hampshire. The cost of replacing a septic system in New Hampshire could be in up wards of $15-$20 K. This article talks about the proper inspection method for inspecting a septic system and how to evaluate it’s overall condition. Whether you own a home, selling or looking to purchase, a full evaluation of the septic system should be a consideration.

Evaluate the plumbing components inside the home:

I inspect all of the interior plumbing fixture’s for proper connections. I also make sure all the waste lines are properly discharging into an approved waste system. Water treatment systems can be harmful to septic systems and I evaluate where the discharge of these systems go.

Examine the inside of the treatment tank:

I open the tank and examine the inlet and outlet baffles and determine the volume of the treatment tank. I inspect the visible parts of the tank for cracks, water infiltration, corrosion, and leakage. I also take a sample from inside the tank with a sludge sampler. Similar to what is used in waste water treatment facilities. By examining the sample I can determine the amount of sludge, liquid level and scum layer. This allows me to understand whether the tank is healthy and if it needs pumping.

Distribution Box:

I inspect the distribution box for corrosion, leakage and cracks. I also make sure the D-Box is level to ensure equal flow to each pipe in the leaching field.

EDA*, ( Effluent Disposal Area ) or leach field.*

I will determine the location and size of the EDA. Test hole’s are hand dug in different locations throughout the EDA. This allows me to examine the condition of the EDA as well as how much saturation is present. A full evaluation of the EDA is critical in determining the overall condition of the septic system.

Vacant homes:

Septic inspections can still be performed on vacant homes. Sometimes a hydraulic load test will be done by running approximately 150-200 gallons of water into the system. Septic dye may also be used to determine flow.


My New Hampshire septic system report is comprehensive and easy to read. I include digital photographs for a better understanding of the system, components and condition.

For more information please visit:

We don’t have a training and licensing requirement for septic system evaluation here!!

Hi Brian,
When the designer engineers the new system they may include the existing tank to stay, this will be up to NH DES to approve. In most cases, at that point you are probably better off with a new tank.

Gray water from treatment systems can go into a dry well and it’s encouraged. Backwash from water treatment systems can and will kill a healthy tank.

Hydraulic load testing is not a great idea. A good evaluator should be able to examine the system and tell whether it has flooded in the past. Evidence can be seen by staining in the treatment tank, the D-box as well as in the EDA. Flooding a system can aid in the evaluation but sometimes requires a return trip the next day to observe absorption.
Hydraulic load testing should never be done through the homes plumbing system. Dumping that much water into the treatment tank will disturb the sludge and break it apart, pieces of the sludge layer can then float into the liquid layer and be carried out to the EDA, thus clogging the EDA. Hydraulic loading should be done through the outlet baffle or preferably the D-box.

Hydraulic Load testing is always recommended for homes vacant more than 7 days.
Also recommended if the number of current occupants are 2 or less.

It is very apparent that all states must inspect private systems different.

Joe, do you normally do the hydraulic test through the home’s plumbing system or through the tank or D-box?

Load test may be made thru Interior or introduced to the system thru the Exterior

Septic inspection now costs over $500 here.

Hydraulic Load here is $685
$275 Additional if Homeowner refuses use of the Well
and Tank trucks need to be brought in…

Refusal of use of H2O Well
ranks H2O Well as Failed…

Joe, do you see many fabric based systems build with septic sand VS a stone and pipe system? They are popular around here because of their compact size, many are going into premature failure due to the contractor using cheap material under the EDA, (usually back fill from the site), There is a 7 year old sub-division here that all the systems are starting to fail because of improper material under the bed. Cost to replace is 12-15K

Here is an example from todays inspection and why I don’t like using the home’s plumbing system for a hydraulic load test.
Home is 15 years old. 1500 gallon treatment tank, D-Box with a stone and pipe EDA.
When the underground irrigation system was installed the D-Box was struck with the Ditch Witch resulting in not only the cover being dislodged but the D-Box itself is broken. For the last 7-8 years ground water and soil have washed into the D-Box creating a thick black sludge layer in the bottom of the tank. Had a hydraulic load test been done on this system more than likely the introduction of a couple hundred gallons of water would have disturbed the sludge and caused it to migrate through the laterals and possibly clogging them.

Buyer was sure glad they hired me septic system inspection.

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From todays inspection. 60 year old dry well for a seasonal cottage still working with no signs of failure.

Re-inspected the broken D-Box yesterday. It was repaired with hydraulic cement, if fact the entire inside of the box was coated. I called the MFG. and they said it has been done and acceptable but they don’t know how long it will last.
I completed the hydraulic load test and everything looked good. I recommended re-inspecting the system in one year to make sure everything is still intact.

Note the inside of the tank/repair. septic dye. inspection hole in EDA

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I personally do not inspect the systems.

I work with a company that has been in business many years with many generations.

For all Load Tests, they guarantee the entire system for 1 year.

With systems costing anywhere from $18,000 to $40,000 in this area (with health department review and permitting), the $600 - $1000 dollars for a load inspection is money well spent…

(Dye never used in this area except to verify connections)

Thanks for the info. Joe. I like to hear how septic inspections are done throughout the country.
Septic inspections in NH are on the rise due to the change in rules by NH DES. One of the biggest problems I see is with the newer systems. Many are built without using the proper material as specified by the MFG. There have been documented failure’s in my area on systems in as little as a couple of years.

During the building boom of the last few years contractors cut corners anywhere they could and septic systems are no different.

Check out this article in the local paper

Here is a follow up article

I have an Inspection scheduled for Tuesday (New Construction)
where we will be conducting a 2 day hydraulic load test.

It is sometimes difficult to convince a Buyer that “NEW” is not synonymous with “Installed Correctly”.

Let me know how it goes. Take some pictures and post them if you can.

From yesterdays inspection. 20 year old system. I had a copy of the plan but it wasn’t accurate. EDA has small growth covering the entire field. Took me about an hour or so to find the D-Box. Other than small roots making their way under the cover, the tank and D-Box looked great. Dug an inspection hole in the EDA and once I got past the roots and top soil the septic sand and stones looked great. Seasonal home with little use. Did a hydraulic load test and the EDA absorbed everything fine.

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From the same inspection as above. Notice very little staining in the inlet and outlet inverts. This indicates the system has never flooded and is considered young in age even though the home was built 20 years ago. I did recommend the tank and D-Box be pumped and cleaned.

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