I'm moving into a new (to me) house with concrete septic tanks. The closest one is 5' from the slab on the front on the house. We want to install a patio there and would like it to extend about 7' from the house if possible.

I exposed the entire top of the tank and don't see any way to clean it out. Is the entire top the lid? There are two holes about 8" diameter on opposite sides that appear to be filled with concrete. Not sure if those were the old access points and the tank has been filled in or something. House was built in 89, assuming tanks are original.

The previous owners had the tanks emptied about 3 weeks ago and I didn't see any signs of significant dirt dug up. Definitely not enough to remove the entire lid. It's overgrown with grass and would have been obvious if it had been removed recently.

Looks like a circular concrete top? With that age, I would have expected a rectangle with two access points larger than 8 inch diameter. Knee jerk is could this be an old cistern?

Perhaps drill a hole into the lid to see what you find? Also could dig around until you found pipes.

Our two have rectangular access points. Septic guy used a long pry bar to get them off to get the hose down in there

You don't see anything like that?

How did previous owners "drain" it? Is there a clean out somewhere or what? Could you snake a camera in there?

Honestly I'd just pave over it since it's a patio and not an industrial shop floor; I'd put in some extra steel if I were worried.

There is a cleanout in the 5' between the house and the tank. I guess it's possible they went in that way.

maroon barchetta said:

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Our two have rectangular access points. Septic guy used a long pry bar to get them off to get the hose down in there

You don't see anything like that?

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It's possible it's a rectangular tank with two tops but it would be huge if so. I'll try to dig a little deeper around the tank to see what I find

I think maybe you're looking at the lid in the last pic. Here's mine

I think you're right but there is no handle on it. No way those lids were removed 3 weeks ago. Grass was grown over solid.

Ours looks a lot like the one Hondo posted. About a 3' diameter circular lid with a chain set in the concrete.



ETA - I had a contractor come out and put a riser on ours not long after we bought the place.

Ok, installer here. The small holes are access points over the inlet and outlet lines. Required by tceq. No doubt the handles for the lids have rusted off. Probably could lever them out with a couple of large screwdrivers, but they're not going to be big enough to clean it out properly. If it was supposedly cleaned out 3 weeks ago, you would notice the grass disturbance yet, so I think he's pulling your chain on that. If installed in 89, you actually should have 2 tanks in a series, unless it's long enough to have 2 compartments, which from your pictures, it isn't. For a proper cleaning, I would remove the entire lid. Doesn't look that big, and doubt it's over 2-3 inches thick.

Just making sure, this is the current septic tank and not an old one?

Not sure how new the house is, but if they had a new system put in, they could have abandoned the old one and not reclaimed it.

And we always used round tanks, as it is inherently stronger against ground pressure. And no I wouldn't cover it with a patio, as you will need to clean it out again, and you really don't want to have to break it up when things don't flush.

Easy way to tell. Use a couple of screwdrivers to pry up the port closest to the house, have the wife flush toilets while you watch. You'll see the flow coming in.

There is another tank in series, haven't bothered to dig that one up.

We have a receipt from the seller claiming it was pumped. Is it possible they just pumped it from the cleanout?

I'll try to get one of the plugs out to see if the tank is still active or if it's been abandoned.

Normally you will have 3 layers inside the tank. Scum layer on top, water layer in the center, and sludge on the bottom. The sludge layer is the one to worry about. Depending on how deep the tank is, 1.5-2 ft of sludge, it needs to be pumped. You don't want it getting up to the outlet pipe bottom, as then sludge fills up your laterals. Don't know your experience with septic systems, but keep grease out of the tanks as much as possible. Germ killing products like lysol kill the bacteria that break down the solids. Kotex and Tampons tyhat go in will have to be taken out, as well as flushable wipes. Don't have laundry day. Do a load or so a day, that way you don't flood the system and push solids out into your leach lines. Sorry for the essay, but it's cheaper to treat one right than it is to repair it!

This reminds me that I need to schedule some pumping.

Please keep going. I have no experience with this and need to learn.

Is it likely that the tank has a baffle in it which is why there are two covers? I'm going to try to dig up more tomorrow to verify if the tank is even in service.

Really appreciate all the info.

If it's a stub-up clean out, I'd say doubtful. The hose bend radius likely exceeds the radius of the 3" tee.

As for placement of the patio, I wouldn't recommend it. Concrete tanks do sometimes fail (break-down) and need to be replaced.

I'd just call the company that cleaned it out and have them tell you how it was done.

I have a three tank system and only had one riser accessible.

I dug up the "lids" to the other two tanks and handles had completely rusted off, so I pryed out the concrete lids, got two 12" length pieces of 20-inch diameter HDPE water pipe and made me two new risers. Then made new lids out of 24" concrete pavers.

Usually by '89 there weren't many people using baffles any more. Easier and cheaper to use a t fitting on the pipes in and out. Which is another thing to note. If you decide to open it up, make sure that the outlet line (furthest from the house) has a T fitting. On the older systems, 90 degree bends were used, but yours should have a T fitting I would think. If it doesn't, have one installed. It keeps solids from going directly into your lines, or in your case, into the second tank, which is there to keep liquids only going into your leach lines. The first tank catches most of the solids, the second tank catches any solids that make it through the first. Ergo, the first tank is normally the only tank that requires serious pumping, but if you can keep track of where one of the access ports are on the second tank, it never hurts to check the sludge level in it. Other than that, like i said, don't put anything in it you don't want to have to pay to have removed, if you have a garbage disposal, use it sparingly, Try to keep the kids from taking hour long showers! Glad to answer any more questions.

I see a couple of possible "solutions" to your quandary. First, and likely simplest/least expensive, pour your patio slab over the existing tank, being careful to leave a removable lid for access to the septic tank. The second is to simply move the existing tank, which is gonna cost ~ $1,000 +.

Gonna cost more than that!

All of this talk of septic tank pumping and now the only thing I can think of is Kamala Harris.