Raised manhole covers - Can they be lowered for water tanks?

[15gpworlds]

Hi, I've recently moved to Africa. Our house has a number of raised manhole covers which severely restrict garden space. One is for the underground water tank. One for our foul drainge and one for the sewer. We've been told that they cannot be lowered as this may lead to contamination from run-off in the rainy season - and yes we do get ponding of water after very heavy rains (both due to the rain itself and also because of the lack of drainage on the hard surfaces of the compound).

I imagine that there must be a manhole cover that is completely watertight so that even if it floods it will not allow water in to the water tank, but I can't find anything like this - do you know of such a product? Ideally it would be recessed so that we could plant grass over it.

Or are there any other solutions?

Thanks for your help.

[flowjoe]

Just google search internal recessed manhole covers, they have to be air-tight

[seanandruby]

double sealed manhole cover.

[Ted]

I live in Africa and for a long time wanted a recessed double sealed one.

But then I realised that one wants an easily openable one and one that opens with manhole keys is a pain in the xxxx. I need to open my tank surprisingly regularly.

Just think - if and when:

- your water pump breaks you may need buckets of water regularly
- you have a powercut and your genset is out of diesel you may need buckets of water
- you want to check the level of water in your tank
- mains water shuts off and you have to truck water in to fill your tank you will want to be able to open the tank easily and quickly
- someone decides to use your manhole keys as a tool and breaks them it will then be a pain opening your manhole cover with an improvised tool
- you lose or break your manhole key you will need to order new ones from Europe or wherever

I'll take a photo of the cover I got a welder to knock up for me.

It is unsightly but practical and prevents rain and surface water from entering.

All my neighbours have copied this design and it is a new line of business for the welder!

[Ted]

For the foul drainage and sewer an imported recessed double seal is good.

[local patios and driveway]

I have one on a cess pit that is sealed with a rubber seal and 4 screws. Pretty simple.

[Ted]

Here is my water tank cover:

The pitch of the cover means rainwater does not pool on top of it.



The use of angle bar for the frame also means that surface water on the driveway cannot enter and contaminate the tank's contents.