--- title: "Why Washing Solar Panels Matters: Benefits, Risks, and Best Practices" description: Discover the importance of washing solar panels, its impact on energy production and financial returns, and best practices for maintaining commercial-scale solar systems. image: https://www.transformenergy.com/hubfs/Dirty%20Solar%20Panels.jpg --- [![Transform Energy Logo](https://www.transformenergy.com/hs-fs/hubfs/Transform%20Energy%20Logo.png?width=147&height=43&name=Transform%20Energy%20Logo.png)](https://www.transformenergy.com/) - [ABOUT](https://www.transformenergy.com/about) - SERVICES - [INSTALLATION](https://www.transformenergy.com/solar-installation) - [ASSET MANAGEMENT](https://www.transformenergy.com/asset-management) - [ELECTRICAL](https://www.transformenergy.com/electrical) - [ROOFING](https://www.transformenergy.com/roofing) - [BLOG](https://www.transformenergy.com/blog) - [PROJECTS](https://www.transformenergy.com/projects) [CONTACT](https://www.transformenergy.com/contact-us) # Why Washing Solar Panels Matters: Benefits, Risks, and Best Practices Solar PV systems are designed to operate reliably for decades, but like any piece of outdoor infrastructure, their performance is influenced by environmental conditions. One of the most common—and most overlooked—factors impacting solar production is soiling: the accumulation of dust, pollen, agricultural debris, bird droppings, and other contaminants on the surface of solar modules. For owners of commercial-scale solar portfolios, especially in California, understanding when and how to wash solar panels can materially affect both energy production and financial outcomes. Production Impacts from Soiling Soiling reduces the amount of sunlight reaching the photovoltaic cells, directly lowering energy production. Numerous field studies and operating datasets (e.g., [NREL](https://www.nlr.gov/pv/soiling?utm_source=chatgpt.com), [ScienceDirect](https://www.sciencedirect.com/science/article/pii/S2590123025008874?utm_source=chatgpt.com)) across show that soiling impacts can commonly drive losses of 15–30% or more. In California, these losses are exaggerated by the fact that these losses typically occur in the summer through fall: *•    When solar production should be at its peak* *•    When utility prices are at their highest* In most regions throughout California, long dry seasons often mean that natural rainfall is insufficient to meaningfully clean modules, allowing soiling losses to compound over time. Financial Implications for Commercial-Scale Solar Projects Lost production translates directly into lost value—but the magnitude depends on market structure, ownership model, and tariff design. For commercial-scale solar PV systems in the California electricity market, soiling losses can impact: *•    Reduced Utility Bill Savings under NEM or RES-BCT* *•    Reduced Renewable Energy Certificate (REC) Revenues* These soiling losses can easily equate to hundreds of thousands of dollars in losses annually across multi-megawatt portfolios. The key is determining whether the incremental production recovered through washing exceeds the cost of the service—a question best answered with site-specific data. Best Practices for Washing Solar Panels Not all washing programs are created equal. Based on operating experience across commercial and public-sector portfolios, best practices include: *Wash Frequency* •    Most commercial sites benefit from one to two washes per year •    High-soiling environments may justify targeted or seasonal washes *Timing* •    Schedule washes during peak production seasons (mid-to-late summer) •    Avoid washing immediately before forecasted rain events •    Use performance data to identify periods of elevated soiling losses *Methods* •    Use deionized water and soft-brush or low-pressure systems •    Avoid chemicals or abrasive tools that can damage module coatings •    Ensure vendors follow manufacturer and warranty-compliant procedures *Data-Driven Decisions* •    Pair washing with performance monitoring and trend analysis •    Validate post-wash production gains to inform future maintenance planning How Transform Energy Asset Management Can Help Effective panel washing isn’t about doing more—it’s about doing the right amount, at the right time, for the right reasons. Transform Energy Asset Management helps commercial and public-sector solar owners: •    Quantify soiling losses performance data •    Evaluate the financial return of panel washing  •    Develop right-sized maintenance programs aligned with portfolio economics If you’re unsure whether your solar assets being properly maintained, we’re happy to help assess your portfolio and design a data-driven maintenance strategy. [Reach out to Transform Energy Asset Management](mailto:David.burdick@transformenergy.com) to learn more. ## Powering Progress Energy [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [Is Your Solar Portfolio Actually Managed - Or Just Maintained?](https://www.transformenergy.com/blog/is-your-solar-portfolio-actually-managed-or-just-maintained) Many solar and battery owners assume that if their systems are operating and a contractor is performing preventive maintenance, thei [Read More](https://www.transformenergy.com/blog/is-your-solar-portfolio-actually-managed-or-just-maintained) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [How Much Solar Production Loss is “Normal”?](https://www.transformenergy.com/blog/how-much-solar-production-loss-is-normal) Every solar asset loses some production over time. That is expected. The challenge is figuring out when declining performance is sim [Read More](https://www.transformenergy.com/blog/how-much-solar-production-loss-is-normal) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [What Your Solar Monitoring Platform Isn’t Telling You](https://www.transformenergy.com/blog/what-your-solar-monitoring-platform-isnt-telling-you) Most Monitoring Platforms Only Tell Part of the Story [Read More](https://www.transformenergy.com/blog/what-your-solar-monitoring-platform-isnt-telling-you) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [The First 90 Days After You Acquire a Solar Asset](https://www.transformenergy.com/blog/the-first-90-days-after-you-acquire-a-solar-asset) You just acquired a property with solar. [Read More](https://www.transformenergy.com/blog/the-first-90-days-after-you-acquire-a-solar-asset) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [Solar Pain: Real-World Problems Owners Are Facing Right Now](https://www.transformenergy.com/blog/solar-pain-real-world-problems-owners-are-facing-right-now) Over the past several weeks, I’ve talked with several companies and public agencies facing significant solar challenges. • A propert [Read More](https://www.transformenergy.com/blog/solar-pain-real-world-problems-owners-are-facing-right-now) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [Why Most Solar Portfolios Underperform (And How To Fix It)](https://www.transformenergy.com/blog/why-most-solar-portfolios-underperform-and-how-to-fix-it) Over the past decade of supporting organizations with managing solar portfolios, we’ve seen a consistent pattern: [Read More](https://www.transformenergy.com/blog/why-most-solar-portfolios-underperform-and-how-to-fix-it) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [Is Your Solar Ready for Peak Summer Production?](https://www.transformenergy.com/blog/is-your-solar-ready-for-peak-summer-production) For organizations that rely on solar energy to reduce utility costs, summer is the most important time of year. Electricity rates ar [Read More](https://www.transformenergy.com/blog/is-your-solar-ready-for-peak-summer-production) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [Why Washing Solar Panels Matters: Benefits, Risks, and Best Practices](https://www.transformenergy.com/blog/why-washing-solar-panels-matters-benefits-risks-and-best-practices) Solar PV systems are designed to operate reliably for decades, but like any piece of outdoor infrastructure, their performance is in [Read More](https://www.transformenergy.com/blog/why-washing-solar-panels-matters-benefits-risks-and-best-practices) [Asset Management](https://www.transformenergy.com/blog/tag/asset-management) ##### [How to Evaluate the Financial Health of Your Solar Portfolio](https://www.transformenergy.com/blog/how-to-evaluate-the-financial-health-of-your-solar-portfolio) A high-performing solar portfolio doesn’t happen by accident. Even well-designed systems can drift from plan—through equipment degra [Read More](https://www.transformenergy.com/blog/how-to-evaluate-the-financial-health-of-your-solar-portfolio) [![Footer Logo](https://www.transformenergy.com/hubfs/Footer%20Logo.svg "Footer Logo")](https://www.transformenergy.com) - [About](https://www.transformenergy.com/about) - [Blog](https://www.transformenergy.com/blog) - [Projects](https://www.transformenergy.com/projects) - Services - [Installation](https://www.transformenergy.com/solar-installation) - [Asset Management](https://www.transformenergy.com/asset-management) - [Electrical](https://www.transformenergy.com/electrical) - [Roofing](https://www.transformenergy.com/roofing) ##### Contact Phone: [209-809-1300](tel:209-809-1300) Email: [sales@transformenergy.com](mailto:sales@transformenergy.com) [Get In Touch](https://www.transformenergy.com/contact-us) © 2026 Transform Energy. 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