Drain pipes backing up from septic tank

..Brian..

So we just moved into a late 70s bungalow and in the last month, the sewer pipes have backed up twice. The septic tank was emptied two weeks ago so that's grand.

I spent about a hour rodding the bejesus out of the pipes from the inspection manhole in the garden back to the tank and it eventually cleared. I then emptied the bath and the thing backed up again! Water was flowing from the house, passed the inspection manhole and I could hear it splashing into the tank but it still backed up.

The previous owners were a couple in their 60s on their own. I have a family of 5 so it's safe to assume the system is getting more of a hammering then it has in many years.

What's my next step? Is 4" pipe standard or can you get wider diameters for sewerage? Would the pipe be entering the septic tank too low and cause it to back up after heavy rainfall?

Will I need to dig up the whole garden or is there any point it buying a couple of more extension kits and trying to push the rods the entire way through until I see them coming out in the tank?

Any ideas at all?!

the_pen_turner

what have you on the end of the rods
you need to have enough rods to go the whole way through.

Sam Kade

There must be someone using lots of toilet paper.

Buona Fortuna

Hi Brian - not in the remotest sense an expert but we have a similar concrete septic tank.

• I'd agree with pen turner. You need to rod the whole thing. Be careful what you use on the end. Don't use something that might get caught in one of the pipe joins. The corksrew is the least risky.
• I'd have thought 4" perfectly adequate. Its not as if all 5 of you discard a bath at the same time.
• When we had problems with the tank backing up it was the percolation area. Its an area of gravel where liquid flows off the tank. Over time soil washes into the gravel and it becomes no good as a soak away.

Best of luck, at least its the "summer", cause they're a bugger to sort out in winter

Buck Turgidson

Well 4" pipes are standard. You said it eventually cleared, but it should flow freely. Were you using a metal spike rod end, you might get a better result with hot water and rubber disk/plunger type rod end.
Bath / sink shouldn't really discharge into septic tank, but that's another story.

muffler

Buck Turgidson wrote: »

Bath / sink shouldn't really discharge into septic tank, but that's another story.

Thats 100% wrong. All grey water MUST discharge to the tank.

Buck Turgidson

muffler wrote: »

Thats 100% wrong. All grey water MUST discharge to the tank.

I knew I shouldn't have put that last line in..... So it is 100% wrong to have a separate grey water system, and all grey water MUST NOT be recycled ? thanks Muffler, good to know.

Anyway lets stick with helping out OP and his drains.

..Brian..

Thanks for the replies guys. I'm using the disk in the end of the rods. I'll get more rods tomorrow to extend the whole way into the tank, only need another 4m or so I'd say, and see what happens then.

What I don't understand is how it cleared and then backed up again. The inspection hole is about 2 foot deep and it was full to overflowing of all kinds of nasty. When I got it drained down to about the last inch, I empitied the bath. The water ran brown for a while but at the end was flowing clear and smoothly. All of a sudden the inspection hole started to fill up again with fairly clear water. It filled up about half way and that's when I gave up!

:Edit: Is the disk the best tool for the job? I was using it working under the assumption that the wave of water running in front of it would have enough pressure behind it to clear the blockage. Would I be better off with the prong style attachment?

Nekarsulm

Possibly insufficient fall on the pipes. ie. they are too level.Any heavy traffic over the lawn that might have displaced a pipe? Buy with a slurry tanker etc.?

..Brian..

It's hard to say, they look fairly level, what would be the most appropriate gradient?

I know that the garden was landscaped a few years ago and two slight tiers were added, I wonder was something disturbed then. Will ask the previous owners. There would be no heavy machinery on the actual garden as there is good access from an adjacent yard.

FortySeven

Grease? It solidifies in the pipes. Did you use hot water to get flow restored? If so the grease can reset after it cools.

Nekarsulm

One inch fall every seven feet. Any greater slope and flows too fast leaving solids behind. Any less and dosent flow fast enough to move the solids.

..Brian..

It was cold water I flushed it it, is hot water better? Also, I only flushed it after I had managed to get it pretty much cleared.

Will see if I can measure the inlet pipe into the tank tomorrow, should be able to roughly work out the fall. In saying that though, it's been working for the last 40 years so I won imagine it's OK.

_Brian

You emptied the septic tank two weeks ago, I wonder though if the percolating area is blocked the tank May have refilled again.

Now, since you got the blockage to move a bit it's possible that the pipe is still partially blocked. In the tank there should be a tee on the inlet to allow the new material enter below the existing crust, watch for this as you rod towards the tank as you don't want to knock it off either.

Grease as mentioned above is a right pain.

My moms system was installed in the 70's and there has developed a slight dip in the pipe toads the tank. Over time grit from waste settled on this dip and needs to be roddes out, it's quite a slow job but only needs doing every few years, something to watch out for. We don't have a rubber flap for the end of the rods so I tie a coalbag onto the corkscrew attachment, it cleans the pipe well and no risk of sticking on anything.

_Brian

Last thought.

The tank "ecosystem" would have gotten quite a shock with the change in use, without doubt ye would have done a huge clean and disenfect when you bought and used much more soap and detergent that previous owners.

You may need to add some biological agent to kick start the tank system again. These can be bought specific for the job. Or the old farmer trick of a dead lamb or chicken added does the trick too, just kickstart the bacteria to break down the waste or it builds up and backs up the tank.

the_pen_turner

op you say you emptied the tank.
why did you do that .

on the second problem . was the tank empty at the time

I would assume it is one of the following.

1
there is a dip in the pipe creating an area where solids build up
2
there is a build up of sediment that is built up around the inside of the pipe and is falling off and blocking it
3
it is the percolation area. its old and probably too small or clogged solid

..Brian..

I got a registered contractor out there two weeks ago to empty the tank as I had thought that was the reason it was overflowing into the garden from the inspection hole.

I know there was a very large percolation area dug out about 20 years ago but I also know the tank was only emptied once or twice since then. Hope it hasn't become solid with sludge.

What's the best way to identify a clog or dip or build up of sediment in the pipe line to to the tank? I've just got an extension rod set so I'll be able to reach the tank from the inspection hatch, will that do it?

the_pen_turner

clogs are usually caused by too much paper being used or the wrong paper being used (some will clog for some reason and not break up). people often put things down the toilet that shouldn't be put down it. feminine products, kitchen waste, grease, domestos, even building waste like skim

sediment is easy enough to spot and fix. when you put all your rods through with the disk you will see sands or small stones . you will see a shell of built up sediments . these are the shape of the pipe and usually 1/4" thick

a dip is harder to spot without digging.
on old timer showed me a trick . get a golf ball and role it down the empty pipe. don't laugh but it works. he showed me on a perfect pipe and it came out the other end . on the one with the dip the ball gets slowed down by the dip or by any water sitting in the dip

..Brian..

Good tip, will try the golf ball trick if I ever get the pipe cleared! I went at it again today with the second set of extensions but I'm still too short by about 1.5m! Will have to get more

..Brian..

Man I was at it for about 3 hours today! The problem was grease and tonnes of it. Big solid chunks that were rock hard. Have it 99% cleared now I would say. Is there any chemicals I can get to break up the rest and flush the pipes?

..Brian..

Man I was at it for about 3 hours today! The problem was grease and tonnes of it. Big solid chunks that were rock hard. Have it 99% cleared now I would say. Is there any chemicals I can get to break up the rest and flush the pipes?

gctest50

You need a grease trap or it'll happen again :

http://www.jfc.ie/GreaseTraps.html

FortySeven

Buckets and buckets of hot water will melt it but you are just moving the problem further up the line.

Brute force and ignorance I'm afraid. You don't want it or any chemicals you use on it in your tank.

Feel for you. It's a sh1tty job.

..Brian..

I've flushed most of it out alright but it's gone into the tank. Will that a use more trouble?

The grease trap looks like what I need but I don't know how effective it will be. The closest I could get the thing would be about 4m from the source. It would definitely help with the 20m to the tank but won't the great just build up before it?

Markcheese

If you've got it cleared now then it should be ok, it took 20 years to build up last time.
Be careful about fats /grease ect going down the drain though...you can get different biological "starters" for septic tanks and i'm sure I saw a grease one in dairygold co-op store a while back.. wether it works or not..

..Brian..

Thanks, yea there's been a ban put in place of any oil, fat or grease going down the kitchen sink! Read about enzymes you can get that replicate in the drains and eat grease so will get some of them. The fact that it's been cleared now, along with no further misuse and the enzymes, I'm hoping we'll be ok!