Around the pool
Why is the ground soggy next to my pool deck?
Soggy ground beside a pool deck in the Phoenix valley usually means water is escaping underground nearby - most often from the pool's buried plumbing, an irrigation line running along the same edge, or the deck's own drainage failing to carry water away. In a climate where nothing stays wet on its own, ground that holds moisture is being fed.
What it usually is
Wet ground here is fed ground
A soggy patch beside a pool deck usually means buried water is surfacing at the nearest low point, which is rarely directly above the leak.
Valley soils do not hold water for fun. Between the heat and the low humidity, a patch that stays damp through an afternoon has a supply. The question is which supply.
Pool plumbing runs from the equipment pad around and under the deck to the wall fittings, so the whole perimeter is a candidate. Irrigation mainline and drip lateral usually run along the same edge, because that is where the planting is. Both are buried at similar depths in the same trench zone.
Be honest about it
What it could be instead
Several explanations have nothing to do with a leak:
- Irrigation doing its job. A drip emitter or a spray head in that bed will keep ground damp on schedule. Watch the patch on a day the zone does not run.
- Deck drainage. Decks are built to shed water somewhere, and after a monsoon storm or a backwash that somewhere is often the same patch.
- Backwash discharge. A waste line ending in the planting bed wets it every time the filter is cleaned.
- Splash-out. The side of the pool people get out on stays damp for ordinary reasons.
Narrowing it down
Reading the patch
| What the patch does | What it points at | What to check first |
|---|---|---|
| Damp every day, including days the irrigation is off | A continuous supply | Turn the irrigation controller off for two days and watch |
| Worse while the pool pump is running | Pool return plumbing | Note the hours the pump runs and when the patch is worst |
| Dries between irrigation cycles | Irrigation, doing what it should | Nothing, unless the zone is running far longer than set |
Ten minutes, on your own
Two days, no tools
The aim is to remove one supply at a time until the patch tells you which it was.
Turn the irrigation controller off for two days
If the patch dries, irrigation was feeding it. If it does not, irrigation is eliminated.
Then leave the pool equipment off for a day
Keep the level above the skimmer mouth. A patch that improves points at the pool's pressure side.
Check the auto-fill and the backwash line
A running auto-fill or a waste line discharging into that bed explains a damp bed without anything being broken.
Read your meter with everything off
It covers the whole property at once, and it is the one check that separates a pool problem from a house supply problem.
How urgent is it
Watch the deck, not the grass
A damp patch of soil is not urgent. A deck that is moving is.
Water running under paving takes the fines out of the base, and once the base is gone the slab follows. Cracked, tilting or hollow-sounding deck beside a wet patch should be looked at rather than watched. The same goes for wet ground that is tracking towards the house rather than away from it.
If you call us
How the patch gets traced back
The pool lines are pressure tested first, because that is the fastest way to include or exclude the largest suspect. If a line will not hold, acoustic listening and line tracing follow it to a point rather than a stretch.
If the pool holds, the irrigation gets isolated zone by zone and the same listening is applied to the mainline. Where the ground is too saturated to hear clearly, we wait for it to draw down rather than guess. See irrigation leak detection and underground leak detection.
Straight answers
Wet ground questions
Does a wet patch mean the leak is right underneath it?
Usually not. Caliche layers in Valley soil carry water sideways, so water surfaces at the nearest break rather than above the fault. The patch is where the water got out, which is why tracing matters more than digging at the damp spot.
How do I tell a pool leak from an irrigation leak?
Remove one at a time. Turn the irrigation off for two days and watch the patch, then leave the pool equipment off for a day and watch it again. Whichever absence dries the ground is the one feeding it.
Is soggy ground next to the deck dangerous?
The soil itself, no. Water washing the base out from under paving is a different matter, and deck that has cracked, tilted or begun to sound hollow beside a wet patch should be looked at rather than left.
Why does the patch come back after it dries?
Because the supply has not stopped. Surface drying in Valley heat is fast and means very little; a patch that reappears without rain is still being fed.
Tell us what the water is doing
What the patch does when the irrigation is off, and what it does when the pool equipment is off.
Photograph the patch and the deck edge
A wide shot showing the patch, the deck and the equipment pad tells us a great deal.
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What customers in the Phoenix valley have written. The words are theirs, on listings we cannot edit.
“Humberto has been amazing! Prompt, professional, and patient. He has gone above and beyond, taking the time to show me how to operate the water valves and educating me so I can continue to monitor for future leaks. He identified multiple leaks and made thoughtful recommendations.”
“Beto was very professional, thorough and patient in explaining everything he was doing and why. It was an excellent and well worth it experience, and this is saying something for an architect who had a hundred questions!”
“The owner and operator of this company is everything a contractor should be. On time, honest, competent, reachable, comprehensive. Hope to work with him again in the future.”