Water under the house

[whiskeyjack]

Despite hot and dry conditions for the last month, there is standing water in the crawlspace in our house and I can't figure out where it's coming from.   We just had a rain and all the downspouts seem to be clear and working properly and no pools of water outside the house.   There is a toilet in the lowest level where I assume there is water under the slab since the bolts holding it down are rusted through - the plan is to saw them off and take a look underneath.

Who do I call to look at this and figure out what's going on?

[former player]

Remember that water runs downhill, so the water in your crawlspace has almost certainly come from somewhere higher. The only alternative is a spring or other water source which is rising under pressure.

To check whether it is coming from your water supply, turn off all the water taps and appliances in the house and have a look at the meter - if the flow indicator is moving, you have a leak somewhere in your water supply.  If the water is clean and not coming from your supply, it may be coming from a neighbours' water supply or a water main.  Ask your neighbours if they have the same problem, then perhaps contact the local water supplier to see if they can help.

If the water is dirty/smelly, it may be coming from your waste water system.  Lift each of the drain covers running from the main sewer towards your house in turn, to see if there is a blockage.  If there is a crack which allows water to drain out and it is not visible from one of the drain covers, you will only find out with a professional inspection by a plumber/drains inspector who can send rods or a camera down.

[whiskeyjack]

Thanks former,

I'm going to just muse out loud here and see if I think of anything.   

The water to this toilet was already shut off and in that state, the water meter showed no leaks when checked.

Once the toilet was removed we found that most of the flange was rusted and the bolts were loose.   There is a 3 inch gap around the outside of the flange before the rest of the floor starts with some deteriorated concrete, but I think most of that gap must have been there from the beginning because there is also a piece of wood stuck into the back of it that looks like it was placed to try to level the toilet when it was installed.  The gap is about 2" deep and is quite regularly circular but with crumbly edges.

Some history:  several years ago we had record rainfall followed by a sump failure.   Water filled up the lowest points of the crawlspace and got under the slab and came out under this toilet.   We spent time pulling up carpet and drilling holes in the drywall and running fans to dry it out.    I was not, however, anticipating a 3" wide swimming pool under the toilet so there could have been water sitting there for a long time causing a lot of the rust I'm seeing now.  (Or the toilet could have been leaking slowly the whole time).

The main point - I know that there is already some way for water to get from under the toilet to the crawlspace (and vice versa) - but I don't know the direction of flow.   The crawlspace is still unusually damp and wan't constantly damp before that initial soaking.  But the crawlspace is a big space relatively speaking;  I'm not sure if this toilet leaking could be responsible.   I looked back at past water bills and nothing jumps out at me.

I think I have 1. leaky toilet causes all the (current) problems and water following a path under the house.   2. Flood from years ago caused all the damage I see under the toilet and there's a flaw in the foundation somewhere letting water in.   3. I've got both a leaky toilet and a foundation/drainage problem.   

I'm pretty sure I can eliminate a natural spring forming spontaneously under the house.