Water with nothing in it
Filtered on the truck, so it dries clear and leaves nothing behind.
What is pure water?
It is water run through deionizing resin on our truck until almost nothing is dissolved in it. With no minerals to leave behind, it dries clear on the glass without a squeegee. We use it at air temperature, never heated.
What do we wash with?
Deionized water
Filtered to near zero dissolved solids, about 1 to 2 gallons per panel.
Soft-bristle brushes
On water-fed poles that reach the top row from the roof edge or the ground.
Microfiber cloths
For droppings and sap, worked by hand with pure water only.
Air temperature
Unheated water on cool morning glass, so the panel never takes a thermal shock.
What do we never use?
Soap or detergent
Residue grips the next dust, and some panel manuals rule it out.
Pressure washers
A hard jet can force water past seals and scar the glass coating.
Squeegees and blades
A blade drags grit across the glass. Pure water dries clear without one.
Plain hose water
Tap and sprinkler water carry minerals that dry into white rings.
Panasonic’s EverVolt manual asks for deionized water free of grit, at ambient temperature, with a sponge, microfiber cloth or soft brush. That is how we wash every brand.
Panasonic EverVolt user manual
What do owners ask about water?
Is the runoff safe for my garden?
Yes. It is water with the minerals taken out and nothing added: no soap, no detergent, no additives. It runs off the glass into your gutters the way rain does, and your lawn, beds and shingles see nothing they would not see in a summer shower.
Can I just use my garden hose?
On a ground mount or a single-story array, a gentle rinse from the ground on a cool morning is fine. Hose water can leave mineral spots as it dries, so expect a few. Never climb onto a wet roof. Our clean-it-yourself guide covers the safe way.
Do you need my outside tap?
Usually not, because we carry filtered water on the truck. On larger arrays we may ask to fill from an outside tap and run it through our own filters before it touches the glass. We will mention that when we confirm the booking.
Why not warm water in winter?
Warm water on cold glass sets up stress across the pane. REC’s cleaning guide asks for water at ambient temperature, and so do we. In winter we wash only on dry days above freezing, once the frost is off, so the water runs off rather than freezing.
Will pure water remove hard water spots?
Usually, yes. Fresh mineral rings from a sprinkler or hose dissolve back into deionized water with a soft brush and a little patience. Spots left baking for years can be stubborn; we tell you on the morning what came off and what did not.
Spots from the sprinklers?
Pure water and a soft brush lift mineral rings without scratching the glass.