Can you clean windows in the rain? Why pure water still works

"Are you really cleaning windows in the rain?" It's one of the questions we get asked most, usually with a slightly worried look. It's a fair question. For years the rule was that a rainy day meant a wasted window clean. With pure water cleaning that rule doesn't really apply any more, and here's why.

Why rain used to ruin a window clean

Traditional window cleaning uses soapy water, a scrubber and a squeegee. If rain lands on glass that's just been done that way, it lands on a thin film of detergent. The drops pick up that residue and dry as marks.

Worse, the frames and sills usually don't get cleaned properly with a squeegee. When it rains, the dirt sitting on them gets washed straight down onto the freshly cleaned glass.

So the problem was never really the rain. It was what the rain landed on.

What makes the marks: the dirt, not the water

When water dries on glass, anything dissolved or floating in it gets left behind. That's what you see as spots and streaks: dust, pollen, traffic grime, and minerals from hard tap water.

Rain itself is fairly clean when it falls. The marks you see on windows after a shower mostly come from the dirt the rain picks up on its way down the glass, the frames and the window above.

How pure water cleaning is different

We clean with water that has been filtered to remove almost everything dissolved in it, including the minerals in Market Drayton's hard mains water. A soft brush on a water-fed pole scrubs the glass, the frames and the sills, then everything gets a thorough rinse.

That gives you three things that matter on a wet day:

• No soap left on the glass. There's no film for rain to mix with, so drops have nothing to leave behind.
• The frames and sills are clean too. Rain running off them later doesn't carry dirt back down onto the glass.
• The glass is left rinsed and clean. Rain that lands afterwards is landing on clean glass, so it dries with very little to show.

In fact, a clean window that gets rained on usually looks better afterwards than a dirty one, because there's nothing for the rain to stick to.

Is it ever too wet to clean?

Light rain and drizzle aren't a problem, and we'll keep working through them. There are a few times we will stop or rearrange your clean, though:

• Lightning nearby. Water-fed poles often contain carbon fibre, which conducts electricity, and a long wet pole is the last thing you want to hold up in a thunderstorm.
• Strong winds. A long pole in a gusty wind isn't safe for us or for your property.
• Frost and ice. Water freezing on the glass or on paths is a safety issue, so on very cold mornings we'll start later or come back another day.
• Very heavy downpours. If we can't see the glass clearly, we can't check it's properly clean, so we'll wait for it to ease off.

If the weather means we need to move your clean, we'll let you know. You already get a text the day before every visit.

What about the occasional marks?

We'll be honest: now and then you might see faint marks after heavy rain. That happens when the rain carries a lot of dust, for example after a dry spell or when there's dust in the air from far away. Those marks show on every window on the street, cleaned or not, and they come off easily at your next clean.

The bottom line

Cleaning windows in the rain with pure water isn't cutting corners. It's how the method is designed to work. Keeping to your schedule whatever the weather means your windows never get the chance to build up grime, which is what really makes glass look tired.

If you'd like windows that stay clean through a British autumn, get your price in 30 seconds or send us a message.