The Direct Answer
Yes, for the outside of your windows, pure water is usually better. The minerals are taken out of the water, so it dries on the glass without leaving spots, and a pole means I can work from the ground. For the inside of your windows I still use a washer and squeegee by hand, because indoors there is nowhere for the rinse water to go.
What is pure water window cleaning?
Pure water is tap water that has had its dissolved minerals taken out. The usual way to do it is reverse osmosis followed by deionisation, and the equipment fits in a van. The contractor-written guide on Designing Buildings describes the method this way: the water is pure, so it dries without leaving marks. Designing Buildings, window cleaning using pure water explains the same thing in more technical language.
At Full View, I make the pure water in my van. A water-fed pole carries it up to your windows so I can wash and rinse from the ground. You can read the step-by-step on the outside window cleaning page.
How is it different from a bucket and squeegee?
The traditional method uses soap or detergent in a bucket. You wash the glass, then pull the dirty water off with a squeegee and wipe the edges. It works, and good cleaners do it well. For upstairs windows, though, it usually means a ladder.
Pure water changes three things:
- From the ground. The pole reaches upstairs windows while I stand on the ground. The HSE’s guidance on window cleaning says to avoid work at height where that’s reasonably practicable, and a pole is one way to do it.
- No soap on the glass. Soap can leave a film behind, and old residue is one reason for spots on a first clean. There’s more on that in spots after the first clean.
- Frames can be done too. A soft brush on the pole can scrub the frame while the pure water rinses it, so dirt doesn’t run back onto the glass. Ask me about frames and sills.
| Pure water and a pole | Bucket and squeegee | |
|---|---|---|
| What touches the glass | Water with the minerals taken out | Tap water with soap or detergent |
| How upstairs is reached | From the ground | Usually from a ladder |
| How it’s finished | Rinsed and left to dry | Wiped off with a squeegee |
| Best for | Outside glass | Inside glass |
Why does it dry without marks?
Tap water carries dissolved minerals. When a drop dries on glass, the water goes and the minerals stay as a small white spot. Hard water has more of them, which is why the marks can be worse in some areas. Pure water has the minerals taken out first, so there is nothing left in the drop to dry onto the glass.
That’s also why I don’t wipe the glass afterwards. Wiping would only add streaks to a window that would have dried clear on its own. If you want to know why your windows can look wet when I leave, read why windows look wet after a pure-water clean.
For the step-by-step on how it’s made, see what is reverse osmosis water?
Where pure water is not better
I’d be misleading you if I said it was better at everything.
- Insides. A pole sprays and rinses, and indoors there is nowhere for that water to go. So I clean the inside windows by hand.
- Very neglected glass. If glass hasn’t been cleaned for a long time, pure water may need a couple of visits to bring it back. I’ll tell you if I think that’s the case.
- Delicate frames. Cracked paint, or timber frames finished with oil or varnish, need care around a pole. If you have any, tell me on the form and I’ll decide how to clean them.
- Dirt that arrives afterwards. Dirt from frames, sills and vents can run onto clean glass, and rain can carry dirt too. Pure water isn’t a promise that glass can never get marked.
Common questions
Is pure water safe to touch or drink?
It’s tap water with the minerals taken out, so touching it is fine. It isn’t meant for drinking, and I don’t offer it for that.
Will it clean bird mess?
The brush and rinse shift most of it. Old, baked-on marks may take more than one clean to come off fully, and I’ll tell you if something won’t shift.
Does it work in winter?
Yes, as long as the weather allows. Very cold, freezing or stormy days can stop a visit, and I’ll move it if so.
So which is right for your home?
For most homes I’d suggest pure water outside and a hand clean inside. That’s what my round does: outsides every 6 weeks and insides every 12 weeks, or a one-off if you’d rather. If you live in Wickford or Rayleigh, you can get a quote and I’ll tell you what I’d do for your windows.
