On Fri, 11 Sep 2015 23:14:14 -0700, Don Y
wrote:

On 9/11/2015 4:29 PM, taxed and spent wrote:
"Don Y" wrote in message
...
We're considering installing a 2000G cistern. But, I'm concerned
as to how the area *above* the cistern will be impacted. E.g.,
I'm sure we won't be able to park a *car* over that area as the
cistern would have compromised the ability of the "soil" to
support that concentrated mass.

The question boils down to how *usable* that area above the
cistern will be going forward: walking on it, small groups
of people (party-goers) *standing* on it, etc.

I assume the actual access port will be relatively easy to
protect?

What is the nature of your planned cistern? There are cisterns all over San
Francisco in the middle of intersections with traffic running over them.
Ditto in Europe.

Given this is alt.HOME.repair, I wouldn't assume I was looking to
install something in a roadway! :

Grease interceptors are a form of cistern, and are located in parking lots
behind restaurants, with traffic and parking over them.

... or commercial establishment! The fact that I'm concerned about
supporting any significant mass suggests I'm not keen on building a
STRUCTURE to support such a mass.

What's your deal?

We want to store irrigation (non potable) water. We don't want a big, ugly
250 cu ft container (plastic, stone, etc.) sitting out for all to see
(and wasting space in the yard).

We don't want to have to convert the area above it to a "patio"
just to carry any pedestrian loads, either. Ideally, we want to
bury it (them?) and not have them visibly noticeable *or* have to
cordon off the area telling friends "Don't walk over there because
you'll fall *into* the cistern."
Use a precast concrete cistern - basically the same structure as a
concrete septic tank, and you can do anything you do over a septic
tank.

If you bury a standard plastic tank, you need to be more careful, of
course.