And how to keep them from coming back
If you live in Central Texas and your windows have a cloudy, crusty, won't-wipe-off film on them, you're not doing anything wrong. You just have Austin water. And Austin water is hard.
At River Blue Services, we clean glass across Austin, Leander, Cedar Park, Round Rock, Georgetown, and out to the lake communities around Marble Falls and Horseshoe Bay. Hard water staining is one of the most common—and most misunderstood—problems we get called about. Here's exactly how we deal with it, what you can (and can't) fix yourself, and how to keep it from happening again.
Most tap water in our area runs around 250 TDS (total dissolved solids—the minerals like calcium and metals suspended in the water). For comparison, water that dries to a truly spot-free finish is under 15 TDS. If you're on a well, you may be sitting at 1,000+ TDS.
What that means in plain English: any tap or city water will leave deposits on your glass eventually. It starts invisibly. You won't see it for a while. Then it slowly builds, hazes over, and one day you realize you can't see clearly out your own window—and no amount of normal cleaning touches it.
Those white spots are mineral deposits, mostly calcium, baked onto the glass. Here in the Texas heat, they bond fast.
How serious is it? We once had a customer whose black steel-painted fence turned mostly white from sprinkler overspray. That same mineral load hits your windows every time the sprinklers run.
Before we get into products, here's the rule that explains all of it. To get anything off a window, you need two things:
What that "something" is depends on what the problem is:
That's why your glass cleaner does nothing against hard water. It's the wrong tool for the job. Dish soap can't dissolve a rock.
Here's how we approach it on a real job
After a normal cleaning, we use fine bronze wool pads to see what comes off dry. Sometimes light buildup lifts right off. Just as often, the buildup is well past this stage—which tells us we're moving to chemical or blade work.
There's a clear ranking of acids by strength, and we start at the bottom:
These acids can etch the glass and destroy window frames—metal especially. Muriatic acid gives off dangerous vapors and should never be used indoors. Done carelessly, it turns a cleaning into a replacement.
If we use a razor scraper, we only ever push the blade forward. Dragging it backward across the glass causes micro-scratches you'll see forever in the right light. This single mistake ruins more windows than the stains do.
The most memorable jobs are the ones left too long. When buildup has been baking on for months or years, a single window can take 30 to 60 minutes to properly clean—which means higher cost to you, and even then the results may be disappointing if the glass is already etched.
There's a hidden cost too: the more buildup on a window, the more heat it traps, and the more likely that window is to fail. In some cases, the most cost-effective route honestly isn't cleaning at all—it's glass replacement. We'll tell you that straight, because the alternative is you paying us for an hour of scrubbing and still not being happy.
As Barney Fife would say: nip it in the bud.
Here's what separates a real fix from a temporary one: if you got hard water stains, you'll get them again unless you fix the cause. Cleaning the glass without addressing the source is just resetting the clock. The usual culprits in Austin homes:
People ask about glass coatings and sealants. Here's our honest opinion: we don't recommend coatings for almost any glass. The one exception is something like RainX on windows that sit directly under an AC condensate line, where the dripping is constant and you can't fully fix the source.
For everything else, the answer is simpler and cheaper: a thorough cleaning twice a year keeps your windows in great shape. We scrub every single time we clean, then dry every edge by hand with a clean rag so water can't pool and leave fresh deposits—which means buildup never gets the chance to bond and harden into the etched mess that costs real money to remove.
Want to tackle light buildup yourself? These are the two we trust on real jobs.
Our first move on hard water. Used dry on already-clean glass, fine bronze wool lifts light mineral buildup without the micro-scratches steel wool leaves behind.
Shop on Amazon
A solid middle rung on the acid ladder for heavier deposits—far safer than muriatic acid. Always test a corner first, keep it off metal frames, and rinse thoroughly.
Shop on Amazon(Amazon affiliate links—they support our free resources at no extra cost to you.)
If your windows are starting to haze and your glass cleaner isn't cutting it, don't wait. Hard water staining only gets harder—and more expensive—the longer it sits. Catch it early and a routine cleaning handles it. Let it go for a year and you might be looking at acid work or replacement.
We'll tell you honestly whether your glass needs a cleaning, a coating, or replacement—no upsell.
