Old Septic Tank

[horseshoes]

We're about to redesign our garden having "inherited" another large patch behind ours. There is a VERY wet patch and I'm wondering if it has anything to do with the old disused septic tanks which are both half full of water. We are about to have a mini digger to dig up old roots, concrete etc and I'm just wondering can we completely smash the old septic tanks so that the water would drain into the ground? I can see an old pipe in the tank too, and I'm assuming that the water is supposed to drain into the stream behind our garden. I'm hoping that perhaps The Builder is around to help. T.I.A.

[jomifl]

The water has probably drained into the tanks from you garden. Can't you use them as reservoirs for times of drought.

[horseshoes]

Jomifl, drought? What's that? I live in North Wales! Seriously though. Thanks for your reply. I'd much prefer to get rid of them completely as its really ugly in the garden and takes up quite a large space which I'd much prefer to use for veg.

[The Builder]

If you're absolutely sure that they are not in use, then certainly either ........

Break out one side to let the accumulated water seep away naturally...

Or fill them up with anything the digger might excavate and needs disposing of.

The bottom of the tanks is most likely below the "water table" for your ground. That's why they would always contain accumulated water. They certainly won't be the cause of the wet ground. I'll take a guess that the water level in the tanks is about the same as the stream.

[jomifl]

I used to work on river surveys in North Wales. I distinctly remember a drought, it didn't rain for 24 hours.

[horseshoes]

Thanks The Builder. I'm positive they're not in use. We still have the little outside toilet shed, but no outside toilet has been there for at least 40-50 years. It's now just used as a tool shed. I think you're correct too, abou the level of the stream, although therein lies another problem, although thankfully to ours. The stream runs through farmland and hasn't been maintained for years. I isn't running and is blocked somewhere and during the last storms caused flooding further down our lane. There was a chap looking at it last week. The owners don't live there, but I'm guessing that the water board (?) might force them to clear the stream. Perhaps that might also cure our wet ground.

Going back to the septic tanks. If there's no toilet connected to them, then they ARE dead aren't they? Just double checking!

Jomifl. Actually, I DO remember a drought here in 1976. My husband is a retired firefighter, and I remember I hardly saw him through that summer, as everything seemed to be burning! I was working too, so we used to leave each other notes. Once we even passed n the stairs! He'd been out fighting yet another gorse fire all night and I was just leaving for work! It doesn't happen that often though:-)

[The Builder]

Yes, they're redundant, Horsey. There is just one remote possibility though.
Septic tanks should never be used for rainwater. It's too much water for the tank to work properly. I don't suppose they have any rainwater gullies running to them?

I only mention it because I installed a new septic tank on a re-build once, and I used the old one as a rainwater soakaway, but I did fill it with stone first though. I really doubt that you have anything connected to it now.

It's a good thing to get rid of them. Children and small animals falling in etc.

For your stream/flooding issue. Speak to The Environment Agency. They usually handle that sort of thing.

http://apps.environment-agency.gov.uk/river-and-sea-levels/120552.aspx

[Clanad]

The Builder mentions something in passing that's an important law here in the U.S.; that being any unused septic tank must be destroyed and remaining hole be filled with rock, sand and soil.

Even though you mention the system as being 40-50 years old, the systems, at least here, were connected to drainage fields rather than being left to drain into other watersheds. the drains were usually perforated piping that was buried in sand and gravel trenches usually at least 4 to 5 feet deep. This let the water coming from the septic tank drain naturally and slowly... actually worked very well. his is said only to inform you that there may be additional parts of the system that need to be dug up or destroyed.

But at any rate, you'd do well to check your local regulations to assure compliance (and safety) referencing destruction of the tanks...

[horseshoes]

Thank you for all this information. I find it all very daunting to be honest. I was SO looking forward to having this extra garden and having a nice big veg plot and my usual flower beds, and looking out at it now, it's just horrible. Not helped by it being so flipping wet and miserable. I know it will be nice in the end but its very hard to believe that at present, and this septic tank has discombobulated us!