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Spotty Concrete · Jun 25, 2009, 11:49 AM

We recently installed a new concrete patio, stamped and stained. It is a beautiful leather brown. Whenever tap water gets on the patio it leaves white stains and spots! Our water is quite hard and we have a water softener in the house, but not outside. Is there any type of easy fix - other than mopping!

Perito · Jun 25, 2009, 01:05 PM

Is there any type of easy fix - other than mopping!

Probably not. When the water evaporates, it leaves the calcium, magnesium, or iron salts that are in the water wherever they lie. You can clean that off with acid (not a great idea) or chelants. If you soften the water, you'll leave sodium chloride (salt) behind.

You could squeegee the water off the area and then there wouldn't be as much deposit, but that's as much work as mopping.

water_doctor · Jul 6, 2009, 04:05 PM

As far as the water goes there is not a lot that can be done to stop it from leaving a residue behind. If you have an efficient softener then you won't see much salt residue if you rinsed it off with soft water. Is the patio in direct sun or is it under an awning or covering of some sort. Not that that will solve your problem but if it doesn't evaporate as quickly it's amazing how much will run off those treated steps and not leave as much of a residue. Again sorry it's not a solutions, just some ideas.

Spotty Concrete · Jul 13, 2009, 04:01 PM

I decided to try several different things I have "heard" might work. So, I applied difference solutions to different parts of the driveway. They included, SLR, Baking Soda solution, lemon juice, and white vinegar.

All of them were failures, except white vinegar! So I went back later and applied white vinegar to the worst areas. I let it rest full strength for several minutes and then mopped. The white powdery substance, that had been fixed to the concrete, now smeared where ever I mopped. So I got a bucket of fresh water from the house (softened) and mopped up the vinegar and residue. It was had work, and I am sure the neighbors thought I had lost my mind to be mopping the driveway, however, it was clean! At least, until the next time the sprinkler went off and water ran from the garden onto the driveway.

Another quicker fix, life for a party, on this deep brown driveway, is "red vineger" i.e. cheap box red wine! It stains the white powder for a temporary fix. Then washes off with water.

Thanks for you ideas.

shintao · Sep 7, 2010, 11:27 PM

Why not try a liquid wax on the dry surface. I have used it for spotting a car where the finish flaked.

Second idea, use Thompsons water sealer. When we built a reactor, the labors used the TWS on the concrete, several coats as I recall. That is also good for sealing the grout in your shower, and of course decks.

garfield9 · Oct 8, 2012, 12:40 PM

I have the same problem and know how to clean off the residue. What I'd like to know is there a way to treat the exterior wter system? I have a water softener for the house interior.

Jo Denyer · Mar 21, 2013, 02:21 AM

Hi,
I have a large terrace and only recently, after 16 years, has the problem of white spots arisen. I have not been doing anything differently but it is really insightly. Please have you a solution?

rjbuchan · Sep 7, 2013, 11:46 AM

If you know how to clean off the residue could you share that information? I do not know how to treat your exterior water system. Thanks