Oh man, I had the
worst (well, except for when I fell through the lid of my parent's tank back in college) time with an old house I bought last year. A widowed lady had lived there alone for the last 29 years and we could find no company or records where she had ever had it pumped. I wore my butt out for a full day poking around trying to just find the tank. Then came the digging.
There were 4 lids that were about 2'X4'X4" thick covering the tank. The tank itself was brick with a mastic coating and brick baffles built in. But, I'm getting ahead of myself. Lemme tell you about what I found. Once I had one lid completely dug out all the way around I told my wife to go ahead and tell the company to send a truck out. I bent my lovely 6' Horrible Freight pry bar trying to pry that lid off. I ended up getting about 4 other people to help me and prying with 2 shovels and 2 4' pry bars we finally got the lid to move. That's when I saw it was 4" thick rather than the 2" lids I've seen before. With no real ability to just pick that lid up, quick, we started digging out the next lid so we could slide that lid over on top of the next lid.
That wasn't so bad, just regular ole hard work digging in heavy clay soil. It's once we slid the lid over that I got the surprise. There was nothing there! Or, so I thought. After closer inspection the "dirt" under the lid turned out to be literally a solid mat made from tens of thousands of small roots holding the dirt (not really dirt) solid. By then, the pump truck shows up. The guy running it literally was 72 years old. He took one look at it and said "I'll come back tomorrow afternoon if you can be ready by then".
What?! He took his probing rod and after a while showed me that there was 'liquid' about 18" down from the top of the mat. To demonstrate how sure he knew what he was talking about, he walked right out on the top of that mat and hopped up and down.
It wasn't until after another 3 or 4 hours of literally sawing with a hand saw that we discovered that it was a brick tank. The mass of roots had literally raised all the lids about 6" above the brick tank. Not good! I had to either give it up right then and spend the money to have a brand new system put in or start sawing. Needless to say, the smell wasn't pleasant. It actually was really bad. Later, the 72 year old guy who'd been doing this all his life said the only thing he'd ever smelled that was as bad was a really old grease pit under an old school that he'd cleaned out 30 years earlier. Anyway, I bought 2 gaff hooks and another couple of hand saws and started sawing just on the outside of the tank. That's when I discovered it was brick.
The trouble was that even with 2 guys on the gaff hook, about all they could lift out was about a 12"X12" square cut out of the inside of the tank. The 12X12 squares were literally deeper than they were wide with greenish looking stuff with the consistency of pudding on the bottom of the squares. It took more than 2 days to cut and dig all that root mat out!
Man, talk about
nasty work!! Still, I was happy to finally call the pump truck back out.
He pumped the tank out and stayed a while to not only help (pretty tough fella for his age!) but to give advice. First off, the bricks looked remarkably good for their age and the pumper fella said that the baffles were in perfect condition and that he hadn't seen one like that in at least 20 years. The trouble was I couldn't find any input or output. He literally climbed in and called me in after him with an 18" pry bar. I mean, what could I say? This 72 year old man was already in this brick pit that smelled worse than anything I could imagine. I had to go in with him. On each end he poked rather gently until he found a 4" clay tile entering the tank and a 4" clay tile going out the other end. He poked the pry bar into the field bed side and pulled out a perfectly round 4" plug about 6" long. With a flash light, it looked dry and clear past that plug. The plug on the input side was a different story. He poked and pulled for quite a while and suddenly yelled "Get out!!".
As we were getting out what looked like a perfectly round 4" turd slowly started entering the tank, breaking off and dropping to the bottom about every 18" or so. After that about 50 gallons of liquid (won't exactly call it water) quickly flowed into the tank. He sucked out all the liquid, but the round turds just wouldn't be sucked out. I had to go in with a flat scoop shovel and a 5 gallon bucket. I filled about a dozen buckets full of that rank stuff before the tank was clean. I finished shoveling about the same time lunch was wanting to come back out. Fortunately, I got out first.
Anyway, the old pumper showed me how to use old roofing shingles around the lid to keep roots from working their way into the tank again. I'd never heard of doing so, but he said 40 or 50 years ago that's the way they always did it and said if my tank was done that way to start I wouldn't have had that problem. Once the lids were back on, he had me double line the outside of the lids with old shingles and then put one one row of shingles across each lid seam. He then had me spread dry concrete mix on the outside of the shingles up to about the level of the lids and only then start re-covering the tank with dirt. I then flushed 2 boxes of Rid-X down a toilet to get bacteria introduced into the tank.
The pumper said that the system was in great shape now and would be good for another 50 years if I kept it pumped every 5 or 6 years. I've had a family of 5 living there for about 3 months now and all is well. No slow drains and no bad smell (I used my excavator and buried that nasty mat about 6' deep!). The new grass seems to be doing well and is growing evenly all over the entire back yard with no area greener than any other. The pump company only billed me $140 for their work. I'm very pleased with that and have recommended them to several others in my area. Hopefully nobody else has to go through that but, in retrospect, it sure beat spending $6000 or so to have a completely new system installed.