Do we have any septic system experts in the house?

More of a "what trade" question as I don't really understand which trade I need to call to help me answer a question, and attempts at getting an answer locally have failed so far. Not sure if that's because they don't get the question often or if I'm asking the wrong question.

Anyway, our house and its septic system are about 20 years old. The house is on a hillside that's pretty wet already with a bunch of seasonal springs. Given that a lot of people state that the usual lifetime of the leach field is about 20-25 years and that we have some damp patches in the yard that seem to have some correlation to our water usage, I'd like to get the drain field inspected, essentially to check that it's still functioning properly. I have some concerns about the latter as the PO's maintenance of the house turned out to be non-existent and given some of the other things I found, I wouldn't be surprised if tanks hadn't been pumped on time and stuff flushed down the drain that shouldn't have been (like grease).

The local septic people only tend to deal with pumping and inspecting tanks, not leach fields. I tried to get some pointers from them as to who might be able to inspect the drain field itself, but am drawing a blank. I'm trying to figure out who (as in which trade) I'd need to talk to who can hopefully give me an assessment of the drain field's condition, probably by checking the "distribution" box (the one the drain field lines branch off at) and ideally the actual lines. Preferably without digging up the yard.

Septic people can pump the tank and inspect the first few feet of field line from inside the tank. This will give you a sense of whether trash and grease have gotten into the field lines. 
 

After that, the best you will do is to put a camera in the line. That will only tell you what the visual appearance of the lines are like. It won't tell you how the field is leaching, etc. Any plumber should be able to get someone with a camera (especially the commercial ones). 
 

That's all you are gonna get without digging up the yard. 
 

Don't assume there is an expiration date on your leach field just because a certain amount of time has gone by. If it's well maintained, leach fields can last forever. 

You could also do a perc test in the damp areas (careful not to damage the lines). Limited digging. This would tell you if the soil is absorbing in that area. 

In theory, damp patches in the yard may be indicative of a properly functioning leach field. Clogs are bad. 

In reply to SV reX :

Thanks! It's the "well maintained" part that I have concerns with, based on other issue we've found with the house over the last few years. The guys that pumped the tank did check the tank and the single field line that goes to the distribution box and pronounced it OK, but pointed out the same thing you did, namely that they could only inspect a few feet of the line.

I guess it's time to talk to some plumbers - which are unfortunately hard to find around here - and see if someone can run an inspection camera to give us a better idea of the condition. And if that doesn't get us anywhere I guess I'll have to hire someone who can at least check the condition around what I think is one or two of the field lines that are uphill of the damp patches.

SV reX said:

You could also do a perc test in the damp areas (careful not to damage the lines). Limited digging. This would tell you if the soil is absorbing in that area. 

I'll look into that - the odd thing is that the damp areas are what I think is downhill from one of the lines, at least based on the drawing for the permit for the system. To me as a layperson it almost looks like the water is hitting a layer in the soil and makes its way downhill along that layer rather than getting absorbed deeper into the soil. Plus, as mentioned the hillside is pretty wet in places anyway.

SV reX said:

In theory, damp patches in the yard may be indicative of a properly functioning leach field. Clogs are bad. 

That's good to know and makes it a little bit less of a worry. We haven't really observed much in the way of the typical septic clog and backup - we know what that's like, not the first house with a septic system we're living in.

Regarding maintenance...

There isn't really any maintenance for field lines. Good tank maintenance is the best you can do. Field line issues are tank issues that have overflowed into the field lines. 
 

If the tank has been poorly maintained but has not overflowed into the field lines, then all you have to do is get the tank up to speed. 

Let me correct that a little...

There is one thing that happens regularly that is a field line issue not related to tanks... roots. 
 

If that system was mine, I'd pump the tank, do a visual inspection of the first few feet of the line. Then I'd add some chemicals to the tank to get rid of any roots in the lines. Then I'd begin developing a good anaerobic bacterial growth in the tank. 
 

If I was really worried, I'd camera the lines. 

Stone and pipe systems do typically last 15 to 20 years. The usual chain of events is someone builds or reno's a house and installs or replaces a drain field, and it works just fine as they use a lot of water raising their family. About the time the kids start to leave the field is struggling, but water use is reduced so you don't notice initially. If you retire there it may limp along indefinitely but if you sell to a young family or some other event causes the water use to increase it fails quickly.

A quick easy way to tell is to load test the field. Find the distribution box, and it should be empty with no signs of previous backups. If its empty run a garden hose in at about 3 or 4 gallons a minute ( adjust flow by filling an ice cream pail and timing it) and see how long it takes to back up. It should never back up but the longer it takes the more life you have left. Most older fields will back up in less than an hour. If it fails the test or it is full to begin with you can have a pumper jet and vacuum the lines out but it is a short term bandage. If he jets the lines and the d box overfills it is done.

In reply to bearmtnmartin (Forum Supporter) :

Good word on the load test method. 
 

What if there is no d box?  Can same method be used from tank when empty?

In reply to SV reX :

If there is no D box in a conventional system there is a good chance it was a cash job on a Sunday and life span would be severely limited anyway.

In reply to bearmtnmartin (Forum Supporter) :

It's a single loop with no distribution box. Exactly the way it shows on the approved permit. 

bearmtnmartin (Forum Supporter) said:

In reply to SV reX :

If there is no D box in a conventional system there is a good chance it was a cash job on a Sunday and life span would be severely limited anyway.

After sunset(wink) 6" pipe Dbox with three 4" field lines(5 holers) 30' long no issues since 2014

Septic fields are all about long term acceptance rates. The soil plugs over time and the poorer the soil the quicker it plugs. When they are designed properly you measure the permeability of the soil and figure out how much water the house will use per day, and install the required number of square feet. If you get it right it will last 20 years and if you get it wrong (most of the illegal ones) it will last much less time. If you are careless and damage the soil, or install it on a rainy day, or have a ground water problem you cut the life span dramatically. Some illegal fields are very well done but most are quickly and poorly installed and don't last long. And of course, exceptions to every rule. My dad's single length of hand dug pipe went thirty years.

In reply to bearmtnmartin (Forum Supporter) :

I was still hoping you'd give some feedback on load testing from the tank. 
 

I'm not sure how we got on illegal fields. As noted, mine is legal and fully inspected. 

Thanks for all of the info, this forum delivers (as usual).

I do suspect the system has a distribution box - without digging up the documents for the septic permit, we have either four or five lines going into the drain field, and there is only a single line leaving from the tank.

I would hope we don't have issues with root intrusion - there are no trees on the area of the drain field and the nearest trees are pretty far away (guesstimate 15'+ if not more, depends on exactly where the lines run and how far downhill).

So if I understood the recommendations correctly, basically I should probably start with having someone dig up the distribution box, check for evidence of tank overflow and then run a camera down the lines from there and maybe check how quickly a water flow backs up into said box.

Based on that, perc test around the area up from the damp patches and/or get the lines jetted? Or is getting them jetted not really worth it if we've established that the system essentially doesn't drain fast enough?

Where would a home owner go to find their properties septic permit and drawings?

All I know about mine is that I have 2 1000 gallon tanks, and I need to buy plastic risers or have a custom concrete set made because of their depth and lid diameter. 

Age and layout sure would be nice to know. 

Township? County? State records office maybe?

In reply to RevRico :

In ohio it's at the county health department 

In reply to SV reX :

It makes no differeence whether you have a D box or not. Just run the hose straight into the outlet pipe and watch the tank level. But you have to be careful because there is no room for error if it backs up. The backup will be in the house plumbing. There is usually only a couple of inches of fall in the tank.

Here in Massachusetts, houses have to pass a title 5 septic inspection before they can be sold.  Maybe read up on whats involved with that.  Here we have engineers design the system, installers install them, and pumpers pump them.  I had my plans drawn up by a local engineer.  He did the perk tests, and handled all of the town stuff.  It was involved because neighbor was doing the same thing with the same engineer at the same time.  We both had to drill new wells in addition to septic.  I hired an excavator to move dirt and bring in gravel, but I layed the pipes and oversaw the installation of the tank and d box.  Engineer inspected with town health inspector.  All was good, so we covered it back up.

I have a kinda sorta update - finally found a local plumbing company that actually does septic drain field inspections and repair. They came out today and looked at the system. Turns out we don't have a "normal" system with a distribution box and the drain lines fanning out from them. Because we're on a hill, the system has a set of interconnected (10"?) drain pipes that run across the hillside and are supposed to be level. Due to the lack of distribution box, they could only scope the line from the tank to the first drain line and then dug up the interconnection. Up to this point everything seems to be working OK and the portion of the drain line they dug up does seem to be draining as expected.

Next step of the investigation according to the plumber would be to dig up portions of all four drain lines that I'm supposed to have as per the permit and double check that they're all level and haven't shifted in the ground. According to him - and the explanation makes sense to me - if one or more of the drain lines have shifted such that they "droop" at one end, that can lead to more water accumulating at that end and thus the wet patches/springs we're seeing.

But before I spend several grand on someone going nuts in the yard with a digger, we'll have the tank pumped again - if our working theory about the wet patch/spring being fed (eventually) by water that's been filtered through our drain field, the "spring" should dry up for a few days after the tank was pumped. Which I believe it did the last time we had the tank pumped, but this time I'm actually going to keep a close eye on it.

The good news is that the plumber doesn't think the field is showing signs of failure, but we haven't determined so far if the issue is connected to our septic system or not, so I guess we've got to, well, keep digging...

You may have a drop box system. They work well but are misunderstood. There would be a small box at the start of each run with an inlet from the tank, an outlet to the trench and a second outlet slightly higher to the next lower box.  All the wastewater goes into the first trench until it backs up, at which point it spills into the next trench and so on until the last trench is full at which point it blows out somewhere. But if you keep an eye on it you can plug each trench off as it fills and take it off line so it will dry out. Then when the last trench is full you start over again.

In reply to bearmtnmartin (Forum Supporter) :

Misunderstandings may be wholly on my part - the plumber did seem to have encountered this type of system before, based on the way he explained it to me.

There doesn't seem to be any boxes involved so far, at least not at the connection of the outflow pipe into the pipe in the first trench. Digging up more of the system will likely be the next round, and then we'll find out how the trenches are connected (ie with or without boxes).