Solar panels are designed to be low-maintenance — but that doesn’t mean no maintenance. One of the most overlooked causes of reduced solar output is simply dirty panels. Dust, bird droppings, pollen, and pollution build up on the glass surface and block the sunlight your panels need to produce electricity.

The question most system owners have: how often is actually enough?

What the Research Says

Studies across the solar industry consistently show that dirty solar panels can lose between 15% and 25% of their energy output. A system producing 10 kWh per day at full efficiency might only generate 7.5–8.5 kWh when panels are soiled — a meaningful impact on your electricity bills and feed-in tariff returns.

The rate of soiling depends heavily on your location and environment:

• Coastal properties — salt spray deposits accumulate quickly
• Properties near construction sites — fine concrete dust coats panels fast
• Rural and semi-rural areas — dust, pollen and bird activity are high
• Urban areas with trees overhead — sap, leaf matter and bird droppings
• Flat or low-pitch roofs — rainfall doesn’t self-clean effectively

The Recommended Cleaning Schedule

For most residential systems across Sydney, Central Coast, Lake Macquarie and Newcastle, we recommend:

• Standard properties: Once every 12 months
• High-soiling environments (coastal, construction, rural): Every 6 months
• Commercial systems: Every 6–12 months depending on system size and tilt

After significant dust events, bushfire smoke, or long dry periods followed by rain (which concentrates and bakes residue), an additional clean is worthwhile.

Does Rainfall Clean Solar Panels?

Partly — but not fully. Light rain can wash away loose dust, but it leaves mineral deposits and sticky residue (like bird droppings or sap) behind. Rain also runs off in streaks, leaving bands of residue across the panel surface. If your area has hard water, rainfall can actually leave mineral deposits that reduce output over time.

What Cleaning Method Is Safe?

This is important. Most solar panel manufacturers specify that panels should be cleaned with purified (deionised) water only — no detergents, abrasives, or harsh chemicals. Using the wrong cleaning agent can:

• Leave a residue film that attracts more soiling
• Etch the anti-reflective coating on the glass
• Void your panel warranty

DSK Cleaning uses a deionised water-fed pole system — the same method recommended by panel manufacturers including LG, SunPower and REC. Purified water leaves zero mineral residue, so panels dry completely spotless.

Can I Clean Them Myself?

You can, but there are risks. Walking on or near a roof without proper footwear or safety gear is dangerous. Using the wrong pressure, tap water, or household cleaning products can damage your panels. And without a water-fed pole, reaching panels on a two-storey roof safely is difficult.

A professional clean typically costs less than the electricity savings recovered in the months following — making it one of the better-value maintenance tasks for any solar owner.

Book a Solar Panel Clean

DSK Cleaning services residential and commercial solar systems across Sydney, Central Coast, Lake Macquarie and Newcastle. We use purified water only and carry $20M public liability insurance.

Call 0423 668 766 or get a free quote online.