Septic system due diligence in a large MHP

Hi all,

First post!

I’m under contract to purchase a ~50 pad mobile home park in North Carolina and I’m currently in the due diligence period. There are approximately 45 septic systems in the park. Most of the systems are for individual lots. The remaining systems are shared between only two lots. The individual systems are 1,000 gallon concrete tanks with PVC tees along with gravel drainfields, all with sufficient repair area. The shared systems are 1,500 gallon concrete tanks with PVC tees along with gravel drainfields, all with sufficient repair area.

Most of the systems have filters on them as well. The lots are large and the terrain is hilly, so there should be good drainage.

Thus far, I’ve identified that only 5 of those septic system tanks have been pumped/cleaned in the last 5 years.

The owner claims that there’s no cause for alarm given that none of the remaining 40 tanks have been pumped/cleaned recently. The county environmental health officer also attests that there have been minimal to no complaints about septic systems at the park.

The owner is blocking my attempts to get a septic contractor into the park to dig open the lids to the tanks to perform simple inspections of the fluid levels in the tank along with whether water appears to have come above the tee.

Essentially, I’m being told that I can only have a septic contractor walk the park to investigate whether any water is surfacing from the drainfields.

My question to you all is…what would you do in these circumstances? Ask for a price reduction? Demand access to inspect the tanks (as I have provided to me in the purchase contract)? Something else?

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If there is no cause for alarm then why does the Seller care if they are inspected? Until you answer that I can’t really say what your best next step would be…


Digging up the lids and doing a visual inspection is a very normal request. His refusal raises lots of red flags. What rational does he give for only letting someone walk the park and letting them look for sewer on the ground do to failed drain fields?


So the owner claims that digging up every tank and having them inspected would be disruptive to the tenants and that they’d have to deal with that. They’re also worried that one or more tank lids would get cracked or damaged accidentally.

Lastly, they claim that after creating all that disruption and/or cracking/damaging lids, I may not end up buying the park.

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Are you able to connect to public sewer?

Different point of view; we were selling 4 years ago a park with approximately 50 septic tanks never pumped (45) years) and tree roots were starting to create problems. If I was the seller I would look for another buyer without all the DD on tanks. The novice buyer actually never had ONE TANK opened or filmed. The buyer was more concerned about a Altus survey than sewage system since over 15 years of ownership we never showed an expense or pumped any tanks (this was our 10th park and we had never pumped tanks in the past in the parks we owned. If the design is correct and soils perk normally no problem unless you encounter large number of people the system was never designed to handle. Two families (12 people more) on one tanks will need pumping.
Some soils will never perk without raised beds. A park we just bought has septic tanks we NEVER looked in depth since we knew the soils and saw the design plans and the sizing of the system that was signed off by the State. The former park mentioned is presently for sale and good luck to the buyer since I know the system is at the end of its life (50 years of no tanks pumped) frightening!!!

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@mhp No, unfortunately public sewer is not available (and likely won’t be for many years).

So @carl as a buyer do you inspect the tanks or does the track record “sniff test” pass muster? As a Seller we all want Buyers to do as little diligence as possible…

Never inspected tanks individually–check soil profiles, perk tests and check IF meet city, county, state codes and any reported problems with authorities. DD is really quite simple after 35 years in the business and our first 235 site park we operated our own honey wagon and yes real symptoms of a questionable system are noticeable to a experienced operator. Please note generally we own properties long term and are hands on to most aspects of operations of such–detect a little ??? attitude with last sentence. We were operating parks long before Frank and company started in parks–this form is excellent just keep in mind we have much different experiences such as having the great opportunity of being raised on a dairy farm–we got our hands dirty and were very efficient and excellent operators.

Typically to perform an inspection the tanks have to be pumped. So maybe you could try to sell the owner that his tanks will get pumped for free, and you get to complete the inspections?

Consider the cost if all 50 systems failed after you bought the park…push harder to get the inspections completed, could save you 200,000.00

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Generally, septic tanks should be pumped every three to five years. Inspection, by you or a professional, may show that you need to pump more less often. Regular pumping ensures that solids will not flow from the septic tank into the drain field.
Maintaining a septic system (tanks and leach beds) can be very expensive. I replaced a 1000 gal tank last year that cost me 4K.
It will be expensive to dig up and inspect all tanks. I would insist on inspecting several of the tanks as part of my DD. Keep in mind if you do purchase the park all tanks will need to be pumped. All my tanks have collars to ground level with lids for easy access. This may not be necessary for homes with individual tanks requiring pumping every 3-5 years but in my case I have 5 homes per tank and pump annually.

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I agree.

“If there is no cause for alarm then why does the Seller care if they are inspected? Until you answer that I can’t really say what your best next step would be…”

Apologies for the delayed reply on this thread. I can provide some detail about where things ended up:

  1. We did end up purchasing the park.
  2. Nearly every one of the septic systems was permitted (and mapped!) correctly through the county environmental health department.
  3. In order to satisfy the seller’s requirement, we ended up signing an amendment to the purchase agreement that stipulated that we could only dig up twenty (20) total septic tanks (none had risers) and that all of them had to be hand-shoveled. Further, we had to provide a list of the addresses/lots where we wanted to inspect the tanks before-hand. Lastly, we agreed to put forward a significant amount of cash into escrow prior to closing ($50,000) to address any damage or unpaid bills that may have gone unpaid or unrepaired if we would’ve walked away from the deal. Of course we’d never worry about that since that’s not how we do business.

All in all it was quite an adventure. Since we had twenty tanks dug open, we went ahead and pumped them, too, at our expense. We knew that the financial risk was steep in doing something like this, but it was really the only way to get a sense of the general tank condition, etc.

In addition to the above, I also had the septic inspector walk the park with me just to check for acid burn and sewage rising to the surface on all of the lots. The seller expressly prohibited any intentional drainfield probing.

I’d be happy to share more details with anyone else if interested. This was our first park purchase and performing due diligence on septic tanks was something we just didn’t come across very much in all of the educational materials we read.

Oh, and we ended up pumping all of the remaining tanks after the purchase completed, except for the few tanks that had been pumped within the past year or so.


According to the United States Environmental Protection Agency, average household septic systems should be inspected at least once every three years by a professional septic inspector. However, pumping a septic tank typically happens every three to five years. More information (912)-666-2210

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