Prufloop / Common home problems / Window cleaning / Hard water spots on windows? Why they won't wipe off

Hard water spots on windows? Why they won't wipe off

General home information from Prufloop. Updated October 28, 2026.

The short answer. White spots on windows near sprinklers are mineral deposits left as water dries. Fresh spots usually come off with a vinegar solution or a glass cleaner made for hard water. Spots left for months can etch the glass so they never fully come out. Aim sprinklers away from windows to stop them coming back.

Safety first. Don't scrape tempered glass with a razor blade; it can scratch. Leave upper-story windows to an insured pro.

What you can safely check

Spray a 50/50 mix of white vinegar and water, let it sit a few minutes, then wipe and squeegee.
Use a hard water glass cleaner for stubborn spots. Test a small area first.
Adjust sprinkler heads so they don't hit windows.

When to call a window cleaner

Spots that vinegar doesn't touch
Second-story or hard-to-reach windows
You want screens and tracks done too

What a window cleaner will usually do

Uses hard water removers suited to the glass
Cleans glass, screens, sills and tracks
Tells you if glass is etched beyond cleaning

Asking an AI assistant to book it

Once Prufloop launches (planned for Q4 2026 around Charlotte), you'll be able to ask the AI assistant you use something like this, and it can book a verified pro at a posted price in a real open slot. This is how it's planned to work; no assistant is connected yet.

Example request. “My windows near the sprinklers have white spots. Book an insured window cleaner in Rock Hill.”

Before a job is booked, you see the pro's posted price, including any trip or diagnostic fee. Anything extra needs your OK first. When the work is done, you confirm it's fixed with a quick text. That's Proof of Done™.

Questions

Are hard water spots permanent?

Fresh ones aren't. Spots left on for a long time can etch the glass, which cleaning can't fully reverse.

Does it help to clean windows more often?

Yes. Regular cleaning removes minerals before they bond to the glass.

Can my AI assistant book a window cleaner for this through Prufloop?

Not yet. Prufloop is being built so the AI assistant you already use can book a verified window cleaner at a posted price, starting with the Charlotte-area pilot planned for Q4 2026 in Mecklenburg, Union, Cabarrus, Iredell, Gaston and Lincoln counties in North Carolina, plus York and Lancaster counties in South Carolina. No AI assistant is connected yet.

Are you a Charlotte-area window cleaner?

Free to join. Only pay on jobs completed: 10% on jobs under $2,500, less on bigger jobs, charged when the job is marked done. No lead fees. Founding pros get a guaranteed spot and founding terms locked for 24 months.

Secure your spot

How it works for pros