Why Is My Pool Surface Rough? What causes it and how to fix it.

A rough pool surface is almost always caused by one of three things: etching from aggressive water, scale built up from high calcium, or a finish that has simply worn through. The first two can often be fixed by balancing the water and treating the surface. The third cannot, and it is the usual reason a pool needs resurfacing.

Rough, or just textured?

Some finishes are meant to feel textured. Pebble is the obvious one, and you would not expect it to feel smooth. What we are talking about here is a surface that has become rougher than it used to be: scratchy on the soles of the feet, snagging swimwear, or rough in patches where it was once even.

Cause one: etching

Water that is too acidic, or generally aggressive, slowly dissolves the surface. Over time this leaves it pitted, etched and rough, and it can expose the aggregate beneath. Low pH, low calcium hardness and low alkalinity all contribute. Etching tends to show up across the whole pool and is often worse where water chemistry has been neglected for a stretch.

What can be done: once the water is brought back into balance, further etching stops. The damage already done does not reverse, so if the surface is badly pitted, the fix is a new surface.

Cause two: scale build-up

The opposite problem is water with too much calcium, or high pH. The calcium comes out of the water and forms hard, crusty deposits on the surface, especially at the waterline and on steps. Scale feels rough and gritty, and it traps dirt and stains.

What can be done: light scale can often be treated by correcting the water balance and, where appropriate, a controlled acid wash. Heavy scale that has been there a long time is harder, and removing it can expose a worn surface beneath.

Cause three: the surface has worn out

Every surface wears. Pool chemicals, sun, brushing and use gradually break down the top layer. In a worn pool the finish becomes chalky, rough and patchy, and you may see the aggregate loosening or the surface flaking away, usually first on the steps and around the waterline.

What can be done: nothing cleans a surface that is no longer there. This is the point where a resurface is the right answer. A painted pool that has gone rough is the same story. If the coating is breaking down, see our guide to paint versus resurfacing before you choose the next step.

Why roughness matters

It is not only about comfort. A rough surface is porous, so it holds dirt, algae and stains and is harder to keep clean. It also means the protective top layer is thinning, and the shell beneath is more exposed to water and chemicals. Left alone, roughness usually leads on to flaking, hollow patches and the kind of damage that costs more to put right. Catching it early gives you more choice about what to do and when.

What you can try first, and what to leave to us

• Get the water tested and balanced: pH, alkalinity and calcium hardness. Most rough-surface problems begin here.
• Brush the surface regularly so deposits do not set hard.
• Check whether the roughness is spread across the pool or sits in patches. Widespread points to water chemistry or general wear. Patches suggest local failure.
• Tap the rough patches. Hollow sounds mean the render has lifted, and no amount of cleaning will help.

Be careful with DIY acid washing. Done badly, it can strip more of the surface than you intended. If scale or roughness is bad enough that you are thinking about it, an inspection is a better first step.

How to tell if it needs a resurface

Roughness plus any of these usually means the surface has reached the end of its life:

• Stains that will not shift, covered in our guide to pool stains
• Flaking, peeling or chalky patches
• Hollow-sounding render
• Cracks or water loss

Our signs your pool needs resurfacing guide goes through each one. If you decide it is time, our pool resurfacing page explains the process, and once the new surface is down, caring for a new pool surface covers the water balance that keeps it smooth.