Water in my crawlspace

[Gunny]

During heavy rains water gets into my crawlspace.  I've installed some French drains and I have some sloping I need to do to divert water away from my house.  The crawlspace is trenched and graded to pool the water in one corner where it collects then is diverted outside by a drain which runs through the wall of the crawlspace.  Water never sits in my crawlspace for more than a couple of days after a rain.  Additionally, the crawlspace is well ventilated. I've done a thorough inspection and can find no water damage or mold.  The house is eight years old.  My question: since the water quickly drains out off my crawlspace and never collects for more than a couple of days and the space is well ventilated, should I be worried about temporary water in my crawlspace after heavy rains?

[Fishindude]

It would be preferable to keep the water from getting in to start with.

[Gunny]

It would be preferable to keep the water from getting in to start with.

That's the intent, but not always successful, thus my question.  If I'm unsuccessful from diverting all water, then I having the water in my crawlspace for a couple of days reason for worry. 

[Drifterrider]

Sounds like your ground won't perc (nothing like Alabama red clay).

Is it a few inches of standing water or just puddles?

Have you considered putting in a small well and sump under the house?

[Gunny]

Sounds like your ground won't perc (nothing like Alabama red clay).

Is it a few inches of standing water or just puddles?

Have you considered putting in a small well and sump under the house?

It just a puddle here and there and where it collects before draining to the outside.  I don't think I need a sump pump as the existing drain to the outside seems to drain all the water in just a couple of days.  Water does not stand in the crawl space for longer than a couple of days before it totally drains and dries out.

[Goldielocks]

The couple days worries me. It won't take much for this to become a large problem. Can you improve it so that water leaves in 10 hours or less?

[phred]

if it's only for a couple of days, and then you're sure it dries, then no.  Still, it would be better if the water never got there in the first place.

The only thing I might question, because I don't know, is if the frequent water inflow/outflow has negated the effectiveness of the termite prevention chemicals

This all does assume the crawl space has decent ventilation

[Gunny]

The couple days worries me. It won't take much for this to become a large problem. Can you improve it so that water leaves in 10 hours or less?

I am working on doing some grading on the uphill side of my house to hopefully lessen the problem.  I think I could improve the water drainage from under the house. 

[Gunny]

if it's only for a couple of days, and then you're sure it dries, then no.  Still, it would be better if the water never got there in the first place.

The only thing I might question, because I don't know, is if the frequent water inflow/outflow has negated the effectiveness of the termite prevention chemicals

This all does assume the crawl space has decent ventilation

There currently are no chemicals being used.  I just had an inspection six months ago and was bug free.  There is good ventilation under the house, but still I'm working to eliminate as much of the issue as possible. 

[Cellista]

I have the French drain, plus a sump pump.  The pump goes on every once in a while even after the rain has ended.  No mold, so far.

Is it possible to put a fan down there?  Even a simple window fan will help move the moisture out.

[paddedhat]

Obviously the grading is still an issue, it will be interesting to hear what goes on when that is fixed. What about gutters and downspouts?  Where is the water coming from? Does it weep in the joints in a block wall, or? What's on the floor of the space, gravel, plastic, concrete?

Crawl spaces are a PITA. I have a state of the art one, and treat it a bit like an ongoing science experiment.
 It is  nearly vault tight, no vents, poured concrete wall and floor, spray foamed interior wall insulation from the floor up the walls, and onto the plywood sub-floor, and a dehumidifier. I use a remote read humidistat to monitor the crawl humidity. It goes up after a few days of rain, and down after a dry week, since the thing is basically a hole in the ground, and the ground is all clay. My downspouts extend 10 feet from the house, and I can see reading climb if an extension is damaged or disconnected, and the downspout is dumping water too close to the crawl space wall. I can see reading climb if my gutters get clogged with leaves and overflow against the foundation. This is all in a crawl that gets no actual moisture in it at all. I keep the winter temp above 50* and the year-round humidity below 50%. This is the mold threshold, and the space remains clean, dry and mold free.

My point being that there are a multitude of factors that affect a crawl space, and little changes can have big results.