Here’s a drywell installed in 1966 and still in use. The tank was in good condition and the main sewer line was replaced about ten years ago.
The interesting thing we found here was the backwash for the water treatment system discharges into the main sewer line which is taxing the drywell. In the photographs you can see the well water has a considerable amount of iron in it which has stained the inside of the drywell. This helps with aging the system as we can see the high water mark is just below the inlet pipe.
This system has been inactive for some time but a solid bio mat was observed at the bottom of the drywell. We did a load test and the drywell filled up to the high water mark and started to drain. Our opinion was the system is in it’s later stages of life and replacement should be planned. The new owner plans to use this home seasonally which helps. We also recommended the backwash be removed and installed in it’s own drywell which is allowed. This may help the system last a little longer until a replacement can be installed.
Not Sure why my picture’s wont load correctly, NACHI message board problem I guess. Sorry, the last two are upside down and sideways.
Another good reason to find the D-Box. This is from a 33 year old stone and pipe system set up in a butterfly configuration. A butterfly system has the D-Box in the middle and a leech field on each side, in this case there were four rows of laterals to each side. As you can see in the picture the D-Box is completely full of tree roots.
The owner of this home had no idea there was a problem, they have lived here since the home was built, raised a family and for the last year only one person is living in the home. All of the effluent is mainly draining around the D-Box and the leech field looked pretty good. Minimal staining on the stones with no standing effluent would lead one to believe this system is in good functioning condition.
Unfortunately, due to the extent of root infiltration this system may be in failure and replacement may be required. Because the D-Box was also in very poor condition our recommendation was to have a licensed septic installer re-evaluate to see if 1. The roots can be removed and 2. Replace the D-Box.
Also food for thought. You guys that do dye tests and just run water through the system this probably would have passed.
I wonder where the gang at Penn St got their chart info? All of my tanks (aside from the old buried cars and steel drums) are generally in increments of 500 in my area.
Here I go preaching about D-Boxes again but it’s so important to locate and inspect. This one is more of a velocity reducing box as it’s on a pump up serial system. In this case the D-Box is there essentially to slow down the effluent prior to entering row one.
Subject home is waterfront, 13 years old. Has the treatment tank and pump chamber next to the house but the EDA is across the street on an adjoining lot. This is a large diameter pipe system built on a bed of sand installed in a serial manner. This means effluent flows down row one into row two and so on. Different than a parallel system where the D-Box distributes effluent evenly to each row.
The current owners let the EDA become overgrown with small shrubs and trees which has resulted in root infiltration of the D-Box. Upon opening the D-Box we found a good size root ball which has extended almost three feet into row one. As always we cleaned it out and should be OK for now but our recommendation is to reclaim the top of the EDA and plant grass. The rest of the EDA was found to be in good condition and still in it’s early stages of life.
Also, the owners had unplugged the pump alarm which was indicating a failure. We activated the pump which worked fine and most likely the cause is a defective float switch. Very good news for our client who will get the necessary repairs done and will have piece of mind regarding the septic system, worth every penny we charged is what he said.
Many times when inspecting old homes we find the septic has been replaced and relocated. Old sewer lines are often capped off or removed completely.
This inspection we observed the old sewer line going through the foundation which had somewhat of a cap on it but not completely. A few feet to the left we found another sewer line completely open. At this sewer line I could feel air coming through the pipe and it smelled like an old laundry trap, open drywell my guess.
This home was built in the early 1900s and in the early days the septic system was designed to use the tank for solids only and the grey water would bypass the tank and go directly to the drywell.
Our observations led us to believe the original septic system was not properly decommissioned, removed or filled in and could potentially pose a collapse hazard and further evaluation should be completed.
This one didn’t make it past the septic tank.
51 Year old system, 300 gallon steel tank and unknown EDA.
Dug down to the tank and it started over flowing.
Homeowner. “I’ve never had a problem with it”
Peter, that is part of the external lawn irrigation system, once the snow melts and there is grass to soak up all that nice fertilized water there should be no issues…Deal Killer.
Here is a great example of the inside of a concrete chambered system. This system is 28 years old and has only been used seasonally. We typically will dig along the side of the chambers to examine the stones and look for standing effluent.
Most chambers have side ports just big enough to get a digital camera inside. Taking pictures inside will reveal historically how well the system is operating or where it is in it’s overall life expectancy. Just like any leech field, as the chamber age, the sand gets clogged with bacteria and stops draining. Even in systems that are inactive evidence of ponding within the chamber will be visible along the sides of the chambers and the sand will be grayish black.
In this system we were able to get several picture’s inside the chambers which revealed the system is still in it’s early stages of life, even after 28 years. The sand looks good and there was no evidence of staining within the chambers. Good news for our client.
That system looks brand new, if you install them correctly, don’t abuse the system and maintain them properly these systems can last a long time. Helps that it is seasonal use. Nice work.
Here’s a great example of a newer state approved drywell. This system was approved for operation in 2006 and as you can see the drywell looks new. Located in a resort community this system has obviously seen little use.
On a side note. NH is currently reviewing the use of drywells and are considering not allowing their use in the future. The general thought is when a drywell is designed, the EDA (effluent disposal area) is calculated through the sidewall of the drywell, this is where the square footage of crushed stone is located. But in reality, effluent dispersal only occurs through the sidewalls after a substantial bio mat has formed in the bottom of the drywell. Once the bio mat is established, which may take years, the drywell will start to pond effluent and force it out the sides. The state’s opinion is, until this bio mat has formed, effluent dispersal is through the bottom of the drywell and not the intended sides. As you can see in this example there is no bio mat in the bottom of this drywell and it’s 9 years old. I think many system designers will have something to say about this and I’ll be following it.
I’ve always thought drywells were a very effective means of dispersal as long as there is proper separation to the seasonal high water table. One of the oldest functioning septic systems I’ve inspected was a 65 year old stone lined drywell.
Here’s a great example of a 50 year old drywell.
No standing effluent or high water marks indicating effluent ponding or the drywell flooding out during the spring thaw.
Very nice find.
Last week we came across another D-Box with significant root infiltration. We usually try to clean out the roots while we’re there but the infiltration was so severe and the size of the roots were to large that we were afraid we would damage the D-Box or the laterals. We failed the system and recommended repair by a licensed septic contractor.
Out client asked us to go back and video scope the system after the repairs were completed and we found one lateral still packed with roots which the contractor was unable to remove. Their report stated they cleaned all the roots out of the system and is now in good functioning condition. Guess they didn’t expect us to re-inspect their work.
By they way, any septic inspectors out there on the fence about buying a sewer camera just do it, you’ll never regret it.
Here’s a 15 year old Elgen sand filter system in poor to failing condition.
We video scoped the main sewer line and found the D-Box which was full of dirt and sludge. Two inspection holes were dug in the middle and end of the EDA which has three rows. The first hole (beginning) was flooded and the filter submerged. The second hole (end) was flooded to the top of the filter. Black sand was removed from both holes.
We cleaned the D-Box out and the system was functioning but going from two older people to a family of five will kill this system in short order. This system is being used daily with no adverse conditions known to the owners. Luckily, the sellers were there and saw the issue’s and agreed they would replace it right away.
I know I’ve said it before but if someone did a flow test on this system it might have passed without showing any signs of failure. The septic tank was also pumped last month prior to the owner listing their home and the pumper told them the system was in good condition so they were quite surprised. The only way to truly do a proper septic inspection is to actually see what’s going on under ground.
Another Elgen sand filter system in poor condition. This one is 16 years old, effluent ponding and black sand was observed in both inspection holes.
In addition, the PVC laterals were crushed in both inspection holes due to the weight of the back fill. In NH, prior to 2002, thin walled PVC was used which would crush and eventually split open due to the back fill, after 2002 the rules changes to correct this issue. Although these laterals were crushed they have not split open and effluent is still able to pass through.
In the second photo you can see staining above the filter which indicates effluent regularly rises above the filter and pipe during heavy water usage and slowly drains back down to just below the filter.
Due to the age and poor condition of the EDA we recommend replacement be considered.
Note: We often find with systems like this that are in poor condition and the listing agent and sellers say “it’s not in failure” or “I’ve never had a problem with it” and don’t want to replace it. We always use roof shingles as a comparison. We tell our clients, you can look at a roof, know it’s nearing the end of it’s life expectancy but you certainly wouldn’t wait until it starts leaking to replace it, same with septic systems. The conditions are there to show it’s in it’s later stages of life and should be replaced to prevent back ups in the home or break out at the ground surface. Both of which are considered health hazards.
Well winter is upon us and this morning it’s 3 degrees out.
Once the ground freezes we rely heavily on our sewer camera to assist us so we can do a thorough inspection.
Here’s an example of a pump up system with a D-Box and six row, large diameter pipe EDA. We access the D-Box and video scoped each lateral as well as digging inspection holes around the laterals.
We took some great images inside the laterals which showed very little scum and although 14 years old this system was considered to be in it’s early stages of life.
Once the frost gets 5-6 inches in the ground the camera is a great tool for inspections.
Here’s an interesting find. Home was built in 1928 and appears to be the original stone drywell. This drywell was constructed using small stones and granite and was covered with a large stone.
The drywell was approximately 6-7 feet in circumference and we guessed the depth to be about the same.
The home was used as a vacation home for many years and the last occupants (elderly couple) lived there full time for the last 40 years.
Because of the large stone covering the top of the drywell we were unable to access the inside. We used the sewer camera to inspect it, pre and post load test, and found it to be in good condition.
We also believe this is original to the home as the original cast iron sewer lines were still in service. The treatment tank had been updated at some point and a PVC line was installed from the tank to the drywell.
Pictures are kind of grainy but you can see the condition is above average for the age. The oldest functioning drywell, prior to this one, I’ve inspected was 65 years old. Time to update my list.
