How to check your pool
Typical finish life is 10–15 years for plaster, 12–20 for quartz and 15–25+ for pebble. One sign on younger plaster may need only targeted repair or better water care; hollow spots and widening cracks should not wait through a Colorado winter.
With clear water and high sun, inspect the pool, then feel the steps and benches with your hand and bare feet. The seven sections below explain what to look for and what it means.
1. The surface feels rough or scratchy
Plaster that feels like sandpaper has usually been etched, meaning aggressive water (low pH, low alkalinity or low calcium) has dissolved the smooth top layer. It is one of the most common reasons owners start looking into resurfacing.
Roughness on the steps and swim-out bench shows up first because those areas get the most foot traffic. Scraped toes, snagged swimsuits and algae that clings no matter how much you brush all point the same way. A rough surface also gives algae and stains more to grip, so the problem compounds. Balancing the water stops further etching but will not make the surface smooth again.
2. Stains come back weeks after treatment
When stains return within a few weeks of treatment, the plaster has usually become porous enough to soak up metals and organics. Healthy plaster can be cleaned; worn plaster keeps absorbing.
Brown or rust stains often come from metals in fill water or corroding equipment; green-brown or dark blotches can come from leaves and algae left sitting. If the surface is still smooth, an acid wash may lift stains and buy a few seasons, but it removes a thin layer of plaster each time and can only be done a limited number of times. See draining and acid wash.
3. Gray or dark patches where plaster has worn through
Dark gray patches, most often on steps, corners and the floor near returns, usually mean the plaster has worn thin or through to the shell underneath. At that point there is nothing left to clean or acid wash.
These areas feel rougher than the rest of the pool and stain faster. Plaster is a thin waterproof coat over the concrete shell, and once it is gone in spots, water reaches the shell directly. That is a clear resurfacing sign regardless of age.
4. Hollow spots and delamination
A hollow, drummy sound when you tap the plaster with a rubber mallet or the end of a pole means the finish has separated from the shell beneath it. Those areas eventually pop off as flakes or sheets.
Delamination is more than cosmetic. Water gets under the loose area, and in a Colorado winter that water freezes and expands about 9%, prying the plaster further loose each cycle. The edges of a popped spot can also be sharp. Hollow areas need to be cut out and repaired properly before any new finish goes on, or the new plaster can fail in the same spot. Our crack and hollow-spot repair page explains how we handle it.
5. Cracks that widen every spring
A crack that gets longer or wider from one spring to the next is moving, and moving cracks deserve an inspection. Fine, spiderweb hairlines on the surface (called crazing) are usually cosmetic.
Mark the ends of a crack with a waterproof marker or take a dated photo each spring and fall. Cracks that run through the tile line or coping, cracks that line up with water loss, and cracks that widen after winter are the ones we want to see. Our freeze–thaw guide explains why Denver winters make them grow.
6. Heavy scale at the waterline or on the floor
Gray-white crusty deposits along the waterline tile or rough white patches on the floor are calcium scale. In Colorado's dry climate, evaporation concentrates calcium in pool water, so scale is common here.
Light scale can often be removed and controlled by keeping the Langelier Saturation Index (LSI) near zero and partly draining when hardness climbs too high. Heavy scale that has bonded into rough plaster, or scale that keeps returning on a pebble finish, often means the surface itself has reached the end of its useful life.
7. The pool loses more water than evaporation explains
If your water level drops noticeably faster than normal evaporation, the surface or plumbing may be leaking. Failing plaster alone is not always the cause, but cracks and delaminated areas can let water escape.
The simple check is the bucket test: set a bucket of water on a step, mark both water levels, run the pool normally, and compare after 24 hours. If the pool drops more than the bucket, something is leaking. Find and fix a leak before resurfacing, because new plaster over an active leak doesn't solve the problem.
What to do once you've counted
One sign on younger plaster usually calls for a fix: balance the water, treat the stain or repair the spot. Two or more signs on plaster past 10 years usually mean it is time to plan a resurface.
- Take photos of each problem area with the water clear, plus one wide shot of the whole pool.
- Test your water, including calcium hardness, so you know if chemistry is part of the story.
- Get it looked at before winter if you found hollow spots or widening cracks.
- Plan the timing. Plaster needs about 50°F and up to cure, so Denver resurfacing runs roughly April through October, and spring slots book early.
Most Denver-area residential replasters typically run $8,500–$13,500, with white plaster at $8,500–$11,500. Ranges are estimates for the Denver metro, not a quote. Your written estimate sets the price. The pricing guide explains what moves the number. If you'd like a straight answer on your pool, send those photos for a free estimate or call (303) 952-8700. For a longer view of lifespans by finish, see how often a pool needs resurfacing.