Our fosse has a fissure

[Headers]

We have 2 fosse tanks. Both concrete about 35 years old. Definitely not compliant with current norms. One is only used when we have visitors which is very infrequent.
We had them both emptied today (last time was in 2015)
The man said the water level in the rarely used tank was too low so he emptied it, had a look but couldn’t see anything massive.
So we’ve filled it right up to the top and over the space of a couple of hours, the level has dropped a couple of centimetres.
What are our next steps? Is there a handy guide that anyone knows of? No chance of main drains for us as we’re in the middle of nowhere.

[curtis]

Personally, I would do nothing. Keep checking and see how long it takes to get seriously low. That might give you an idea at what level the leak is.

[RobertArthur]

Water level higher than exit (3)? Overflow? Wait and see next week.

[L Austin France]

Personally, I would do nothing. Keep checking and see how long it takes to get seriously low. That might give you an idea at what level the leak is.

Ditto what curtis said plus;
Does the tank have a drain? if so how do you fill it "right up to the top"?
Presumably the tank is now filled with 'fresh' water & not poo etc & now unused. If it was mine I'd wait until the level ceased to drop to ascertain the leak level & then get in the tank (maybe have to drain more water out to welly boot or wader level) & then check to see what the problem is.
Lots of products available to seal leaks which are not under much pressure. A crack can be sealed with mastic.
Be aware of ventilation requirements before you enter as if tank still has poo etc in it. The gasses can kill if not vented off & can be explosive.Lift both lids if available. A decent vaccuum cleaner BLOWING air into the tank could suffice . Don't suck explosive gas into the vac.
If in doubt get an expert to check it. They're not things for the unwary to enter.
Seems RA beat me to the level thing. Great minds.....

[Headers]

I filled it to the level of the draining pipe but not so it would drain away.
We’re both too old and feeble to be jumping into tanks Im afraid.
I think the crack is about a foot down but who knows. It is affecting one part of the inside of the house so we must deal with it. I’m sure SPANC would condemn the system if they saw it.

[curtis]

Ah, you didn't mention the problem with the house. That's a different situation.
What is happening?

[Headers]

When atmospherics are ‘right’ there is a bit of wall that sweats and some wierd capillary damp on a stone block. They’re nowhere near the fosse but on the same line as the fosse. We thought they were from a dodgy copper pipe that we had replaced about 4 years ago but perhaps the culprit is our fissure. We’ll reassess tomorrow.

[Headers]

Thankyou to all of you for thinking about our problem. It is appreciated.

[Headers]

Well there is definitely something amiss with our tank. The level has dropped back to where it was when Mr B the fosse man said it didn’t look right on Friday.
So now I have a new project…..where to begin.

[curtis]

But, will it go lower?