Pool Leaking? How to Find the Leak Step by Step

Your pool level has dropped more than you expected, and you are not sure whether it is just Bali heat or a real problem. A genuine leak can wash soil away under your deck, corrode nearby fittings, and turn into a costly structural repair if left alone. Here is a practical way to narrow down where the water is going, using tools you probably already have at home.

Signs That You Actually Have a Leak

Before grabbing any tools, rule out normal evaporation. In Sanur's dry season (May to September) a shallow pool can lose one to two centimetres of depth per day from heat and wind off the Indian Ocean. If your level drops well beyond that, or the drop continues even on cool, overcast days during the rainy season, something else is happening.

Walk the perimeter after a full day with the pump off. Look for damp patches in the concrete deck, soft spots where your foot sinks slightly, or a thin film of mineral deposit (white or greenish streaks) running down the tile face. Check the skimmer box, return jets, and underwater lights for weeping seals. In older villas built in the late 1990s or early 2000s, hand-applied plaster often develops hairline cracks that are invisible when wet but show up as a faint dark line once the surface dries.

• Water level dropping faster than 2 cm/day in dry weather
• Wet or soft areas around the pool coping and deck
• Unexplained algae blooms in one corner (stagnant water feeding growth)
• Cracked or missing grout lines along the tile face
• A persistent musty smell near the equipment room

The Bucket Test: Is It Really Leaking?

This takes ten minutes to set up and gives you a clear yes-or-no answer within twenty-four hours.

Fill a clean plastic bucket with tap water from your PDAM supply or rooftop tank until it is about two centimetres above the first step of the pool. Hang the bucket over the edge so its bottom sits just below the waterline. Mark the water level inside the bucket with a piece of tape, then mark the pool's water level on the tile with a waterproof sticker or a small dab of chalk.

Leave both undisturbed for 24 hours. Do not run the pump, do not swim, and try to keep the area shaded if possible. After a day, compare the two marks. The bucket will lose some water to evaporation too — that is normal. If the pool level has dropped noticeably more than the bucket level (say, an extra centimetre or more), you have confirmed a leak beyond simple evaporation.

Dye Test: Pinpointing the Crack

Once you know water is escaping, the dye test helps you find exactly where. You need a few drops of liquid food colouring (any bright colour) or a dedicated pool-leak dye pen. Both work fine; the key is visibility against white tile.

Turn off the circulation pump first. This stops the current from dragging the dye away before you can read it. Squeeze three or four drops of dye into the water about ten centimetres from the suspected crack or joint. Watch closely for thirty seconds. If the dye is slowly pulled toward a line, hole, or gap, you have found your leak point. If it just disperses evenly, move on to the next suspect area.

Important safety note: do not perform this test while chlorine tablets are actively dissolving in the skimmer, and never mix concentrated chlorine with any other chemical. If you smell strong chlorine fumes or feel eye irritation, step back, ventilate the area, and call a professional before continuing.

• Pump OFF during the test
• Work in small sections — one corner at a time
• Use a bright colour (red or blue shows best on white plaster)
• Note the exact spot with a photo so you can show it to a technician

Where Pools in Sanur Villas Most Often Leak

After years of salt-laden air from the beach, thermal cycling between hot days and cool nights, and the occasional heavy downpour that saturates the ground under the deck, certain areas fail more than others.

The most common trouble spots I see around Sanur are: tile grout lines along the waterline (the first 15–20 cm below the surface), the joint where the pool shell meets the coping stone, the gasket inside each underwater light housing, the seal ring on return jets, and the pipe connections just outside the shell near the pump room. In villas with hand-plastered interiors rather than factory-made liners, hairline cracks anywhere along the plaster face are possible, especially after the original cement has aged past ten or fifteen years.

What a Professional Brings That You Do Not

If your bucket test confirms a leak but the dye test does not reveal an obvious crack — for example, if the loss is coming from a buried supply line or a micro-fracture behind the plaster — you need equipment beyond food colouring.

A qualified technician will typically use one or more of the following: an electronic pressure gauge to isolate which side of the system (supply vs. drain) is losing pressure; an ultrasonic acoustic detector that listens for the hiss of escaping water through concrete; compressed-air injection into the pipe network so bubbles appear at the exact breach point; and in some cases a thermal-imaging camera to spot damp patches hidden under the deck tiles. These tools let us find leaks without chipping away metres of concrete by guesswork.

Repair Options Once the Leak Is Found

The fix depends entirely on what we find. A hairline crack in the grout can often be sealed with a two-part epoxy or underwater cement patch while the pool stays partially filled. A cracked tile section may need local re-plastering and re-grouting over a day or two. If a pipe fitting has corroded through, we replace the joint and pressure-test it before refilling.

Larger structural cracks or widespread plaster failure usually mean draining the pool, repairing the shell, applying a new render coat, and re-tiling the affected area — a bigger job that takes several days. The cost varies widely depending on access, materials, and how much surface needs work, so I always ask for photos first and send you a written quote from those images before any visit is booked. No obligation, no surprise charges.

Whatever the repair, once the pool is back in service, keep an eye on the level for the first week. A small residual seep will show up quickly, and catching it early keeps the fix simple.

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