Full Pool Drain & Acid Wash for a Fresh Start

When Your Pool Needs More Than a Regular Clean

Some pool problems cannot be solved with chemicals and filtration alone. When years of mineral deposits have crusted over the waterline, when stubborn stains have penetrated deep into the pool surface, or when a severely neglected pool has thick algae growth embedded into the pebblecrete or render — that is when a full drain and acid wash becomes the most practical solution.

A drain and acid wash strips the pool shell back to a clean, fresh surface. It is the most thorough cleaning method available short of a full resurface, and for many Perth pools it can extend the life of the existing surface by several years while restoring the pool’s appearance dramatically.

Understanding the Acid Wash Process

Why Acid Washing Works

Pool surfaces — particularly concrete, rendered, and pebblecrete finishes — are porous. Over time, minerals, metals, and organic matter penetrate into the surface layer. Regular cleaning methods work on what sits on the surface, but they cannot reach contaminants that have soaked in.

Hydrochloric acid dissolves the very thin outer layer of the pool surface, taking the embedded stains and deposits with it. This reveals the clean material underneath. When done correctly by an experienced technician, acid washing removes staining while preserving the integrity and texture of the pool finish.

It is important to note that acid washing does remove a small amount of surface material each time it is performed. A concrete or pebblecrete pool can typically tolerate two to three acid washes over its lifetime before the surface becomes too thin and requires resurfacing. This is why we only recommend acid washing when it is genuinely necessary, and not as a routine maintenance procedure.

The Role of Professional Equipment and Expertise

Acid washing is not a DIY job. The process involves handling concentrated hydrochloric acid, which is hazardous if not used correctly. Our technicians wear full protective equipment including chemical-resistant gloves, safety goggles, and respiratory protection. We apply the acid in controlled sections, working quickly and methodically to achieve even results without over-exposing any area of the surface.

Drainage itself also requires expertise. Draining a pool incorrectly — particularly in areas with a high water table or after heavy rainfall — can cause the pool shell to lift out of the ground (a phenomenon called “pool pop”) or crack under hydrostatic pressure. We assess site conditions carefully before draining and take precautions to prevent structural damage.

What We Address During a Drain and Clean

Calcium Scale Buildup

Perth’s water — both mains supply and bore water — is high in calcium. Over the years, calcium deposits build up along the waterline and on pool surfaces, creating a rough, unsightly layer that harbours bacteria and algae. Acid washing dissolves calcium scale effectively, restoring smooth surfaces.

Deep-Set Staining

Metal stains from iron and manganese in bore water, organic stains from years of leaf tannin exposure, and algae staining that has penetrated into porous surfaces all respond to acid washing. Stains that could not be removed with in-water chemical treatments are typically eliminated or significantly reduced.

Algae Embedded in Surfaces

Severely neglected pools that have been green for months or years often have algae roots embedded in the pool surface. Even after a successful green pool recovery, you may notice dark staining or a rough texture where the algae was attached. An acid wash removes this residual contamination and provides a truly clean starting point.

General Surface Restoration

Even well-maintained pools benefit from an occasional drain and clean to restore brightness and smoothness. If your pebblecrete has become dull and grey over a decade of use, or your rendered finish has darkened, an acid wash can make the pool look years younger.

Perth-Specific Considerations

Water Disposal

When draining a pool in Perth, the water must be disposed of in accordance with local council regulations. Chlorinated water cannot simply be pumped into the stormwater system. We neutralise the chlorine before disposal and ensure compliance with the Water Corporation’s guidelines and the Environmental Protection Act 1986.

Ground Conditions

Perth’s sandy soil generally drains well, which reduces the risk of hydrostatic pressure issues during draining. However, properties in low-lying areas of suburbs like Mosman Park, Nedlands, or areas near the Swan River may have higher water tables, particularly during winter. We always assess ground conditions and may recommend scheduling the work during the drier months of November through March.

Bore Water Considerations

If your pool is filled with bore water — common in many Perth suburbs to save on mains water costs — the refill water will contain the same minerals that contributed to the original staining. We recommend treating the fresh fill water with a sequestrant as part of the refill process to prevent immediate re-staining.

Pricing for Drain and Acid Wash

Our drain and clean service is priced from $500 to $1,200 depending on pool size, surface condition, and any special requirements such as waste water treatment or access difficulties.

• Small pools (up to 30,000 litres): From $500
• Medium pools (30,000 to 50,000 litres): From $700
• Large pools (50,000 litres and above): From $900

These prices include draining, acid washing, refilling, and a complete chemical balance of the fresh water. We provide an accurate quote after inspecting your pool.

Is a Drain and Acid Wash Right for Your Pool?

If your pool surface is severely stained, scaled, or discoloured and standard treatments have not worked, contact us for an assessment. We service pools throughout Perth including Mount Claremont, Claremont, Nedlands, Dalkeith, Cottesloe, Subiaco, and all surrounding areas. We will inspect your pool and give you an honest recommendation on whether an acid wash will achieve the result you are looking for, or whether resurfacing might be a better long-term investment.