How artificial grass is supposed to drain
Water is meant to pass through perforations in the turf backing, through a permeable jointing layer, through a free-draining aggregate sub-base and away into the ground or a drainage point, all within seconds of rain falling.
Every layer in that chain has to actually be permeable and correctly laid for the system to work — a shortcut at any stage shows up as standing water later.
The most common causes of pooling
A sub-base built from the wrong type of stone, or one that's been over-compacted with fines that clog the gaps, won't let water through no matter how good the turf above it is.
Poor site drainage or falls that were never set correctly during groundworks mean water has nowhere to go even if it does pass through the turf, and simply collects at the low point.
Laying directly onto heavy clay without adequate drainage provision, or without a perimeter drain or soakaway to take the water away, causes the base to become saturated and waterlogged, particularly after prolonged rain.
- Sub-base built from the wrong grade of stone: won't drain water through it
- No falls built into the base: water has nowhere to run to
- Laid over heavy clay with no drainage outlet: base saturates
- Debris or moss clogging the turf backing: slows drainage at the surface
Diagnosing where the problem sits
Pour a bucket of water onto a dry patch of lawn. If it disappears through the turf quickly but still pools nearby a few minutes later, the base drainage or falls are the issue, not the turf.
If the water sits on the surface rather than passing through the pile at all, the turf backing itself may be clogged with fine debris, moss or algae rather than the base being at fault.
Fixing it properly
Surface clogging can often be resolved with a stiff brush, a moss treatment and, where the backing is badly silted, a jet wash on a wide fan setting used carefully so as not to disturb the jointing.
A genuine base drainage failure means lifting the turf, correcting the sub-base to the right permeable specification and falls, and adding a perimeter drain or soakaway connection if there wasn't one, before relaying.
Getting it right from the start
The fix is far cheaper if it's designed in from day one: an open-graded, free-draining sub-base of the correct depth for the ground conditions, falls built in during groundworks, and a drainage outlet planned before the turf ever goes down.
Frequently asked questions
Is standing water on artificial grass normal after heavy rain?+
A short delay while heavy rain clears is normal; water still sitting there hours later, or ground that stays spongy, points to a drainage fault.
Can drainage be fixed without relaying the whole lawn?+
Surface clogging can often be treated in place. A base or falls problem generally needs the turf lifted and the ground beneath corrected.
Does artificial grass need a soakaway?+
On heavy clay soils, yes, a drainage outlet is usually needed since the ground itself won't absorb much water.
Will moss make drainage worse?+
Yes — a build-up of moss and organic debris clogs the turf backing and slows water passing through, even where the base beneath is fine.
Do you guarantee drainage performance on new installs?+
Yes, our artificial grass installations are covered under our 10-Year Guarantee, and there's No Deposit Needed to get started.
Pooling water on your artificial lawn?
Tell us what you're seeing and we'll help work out whether it's a surface issue or a base drainage problem — call 0191 743 3072.