Pool deck drainage in Florida: why water sits and what fixes it

Water sits on a pool deck for one of three reasons: the deck does not fall the right way, the deck drains are clogged or broken, or part of the slab has settled. Good pool deck drainage in Florida means each of those is fixed before a new surface goes down, because a topping poured over a drainage problem keeps the problem and only gives it a nicer finish.

So the order matters. Find where the water goes after a summer storm, work out why it goes there, and only then decide what the deck needs. A new surface can correct some fall, within the heights the coping and the doors allow. It cannot clear a pipe or put sand back under a slab.

Why does water sit on my pool deck?

A pool deck is meant to shed water in a planned direction: away from the pool, away from the house, and toward deck drains or the yard. When that works, nobody notices it. When it fails, you get puddles that stay for hours, a green film where they finally dry, and a slip waiting for a wet foot.

The fall is wrong

Fall is the slope built into the slab. The public-pool rule in the Florida Building Code asks for a deck sloped away from the pool at two to four percent to a drain, and it is a good standard for a private deck too. Two percent is roughly a quarter of an inch per foot, which is not much. A slab poured a little flat, or a shallow dip left when it was finished, is enough to hold a puddle.

The deck drains are clogged or broken

Many Florida pool decks have a deck drain: a narrow channel or slotted strip set into the concrete, with a pipe under the slab carrying water out to the yard. The slot is small and the pipe is long, so leaves, sand, sunscreen scum and grass clippings settle in it. A drain that is full looks fine from above and does nothing.

The channel itself can fail too. Plastic channels can turn brittle in the sun, crack, or come loose from the concrete on either side, and once an edge lifts it is a trip line as well as a leak. Water that gets past a broken channel runs under the slab instead of along the pipe.

Part of the slab has settled

A section that has dropped, usually at a corner or along the pool edge, makes its own low spot, and the fall can end up running back toward the pool. Settlement is a ground problem. Downspouts emptying beside the deck, sprinkler heads aimed at it and leaking pool plumbing can all wash the fine material out from under a slab. Our guide to a cracked pool deck covers how to read the cracks that come with it, and when it is an engineer's call.

How do I tell what is wrong with my pool deck drainage?

Wait for a heavy afternoon storm, or run a hose across the deck for a while, and watch where the water goes. You learn more that way than from any photo of a dry deck.

• Water that collects in the same low spot every time, with dry deck all around it, is a fall or settlement problem. Lay a long straightedge across the spot; a gap under the middle is a dip.
• Water that runs to the drain and then backs up out of the slot is a clog, in the slot or further down the pipe.
• Water that disappears into a crack or along the edge of the channel, rather than into the slot, points to a broken drain or a failed joint.
• Water that runs toward the house or sits against a door sill is the most urgent, because it is heading inside.
• A gap opening between the deck and the coping is a sign of the pool or the ground moving, not of the surface.

Then find where the drain pipes come out. If the outlet in the yard is buried under mulch, sod or a new planting bed, the drain has nowhere to go.

Can a pool deck drain be repaired or replaced?

Usually, yes. A clogged drain is cleared from the open slot and flushed from the outlet end, and a plumber's camera down the pipe shows whether it has collapsed or filled with roots. That is the simplest end of drainage work, and it is worth doing first.

A cracked or loose channel is replaced by cutting the concrete back on both sides, lifting the old channel out, checking the pipe and its fall, and setting a new channel to the same line. The cut is then patched. On a bare concrete deck the patch will show, which is one reason drain work and resurfacing often go together: the new surface covers the repair.

On a coastal deck, plan for salt as well. The metal near the surface, drain grates included, is where corrosion starts, so grates should be stainless or a marine-grade equivalent, specified at the quote rather than substituted on site.

What can a new surface correct, and what has to be fixed first?

Shellcrete by SRQ Modern goes down as a 1½–2 inch bonded topping over the sound slab, mixed on site by our own crews. Because it is placed fresh, its top can be formed to a better fall than the slab under it, within limits. The falls are decided before any concrete arrives, the same as the joint layout. They are part of the formwork, not something a trowel improvises on the day.

The limits are the heights already fixed around the deck. The coping sets the height at the pool edge, and the new surface has to meet it cleanly rather than bury it. The door sills set the height at the house, and the deck should finish below them so water runs away from the doors. Between those two lines the fall can often be improved. If a low spot is deeper than that leaves room for, it is not a surfacing job.

That is why our pool deck resurfacing work starts on site: slope, drainage and the transition at the coping are checked before any number is quoted. A new surface cannot fix any of these, so they come first:

• A clogged or collapsed drain pipe. Clear or replace it, or the new deck drains into a blocked line.
• A broken drain channel. Replace it before the pour, so the new surface meets a sound edge.
• A slab that is still settling, or a base washed out by a leak or a downspout. Fix the cause first; a bonded topping moves with the slab under it.
• A pool that is losing water. Call the pool company before anyone resurfaces the deck around it.

Where should the water go instead?

Away from the pool first. Rain that drains into the pool carries dirt, leaves and fertiliser from the yard with it, and it dilutes water you have spent time balancing. Away from the house second. Then toward something that can take it: a deck drain with a clear outlet, a lawn or bed lower than the deck, or a swale that carries it toward the street.

The deck is often only part of the picture. A walkway that pitches toward the pool sends its rain there, so on a larger job the patios and walkways are planned with the deck as one surface, falls included.

If the work adds new paved area or changes the grade, some Florida cities and counties ask for a drainage plan with the permit. Check with yours before you widen a deck rather than after.

What should I watch for after a new deck goes in?

A new deck should shed water the way it was formed to shed it. A thin film that dries off after a storm is normal. Standing water that never drains on a finished pour is not, and it is worth a call in the first month rather than later. Our post on the first month after a pour covers what else is normal in that stretch.

After that, keep the drains clear. Rinse the slots after a storm brings leaves down, and look at the outlet in the yard now and then. Most drainage trouble on a sound deck starts with a drain nobody has looked at.

If water is sitting on your deck and you want to know whether it needs a drain fixed, a new surface or both, send us photos of the deck after rain for a quote, with the drains and the door sills in frame, or call (941) 253-0400.