As the moisture passes from your walls into your basement air it leaves any minerals in the water behind on the basement walls in the form of this white powdery substance.
Yellow stains on concrete block on basement walls.
This can diminish the appearance of your basement walls.
Change the water occasionally and cover.
The salts are present in the mortar blocks or concrete structure and the moisture is usually attributable to some building defect.
Efflorescence and water stains may explain spalling brick or concrete block foundation walls observed in a basement or crawl space.
Putting aside for a moment all the whining i ve already done above about mold rot bugs and wet basement anxiety efflorescence on a masonry foundation more likely to be a cosmetic issue or a moisture diagnostic.
Use a hose and sprayer outside or fill a bucket with warm water and wipe over the wall with a sponge or cloth.
Concrete stains and cracking associated with rusting iron or steel or slag steel inclusions in the concrete material either by deliberate inclusion as reinforcement or by accident such as stones or scrap containing iron that are later exposed to water and possibly freezing cycles.
A the yellowish stains leaching through the coats of drylok and primer on your walls are an indication that water in either liquid or vapor form still is entering your basement.
Apply a second layer of white vinegar and scrub the stain with a stiff bristled scrubbing brush vigorously for at least two minutes.
Efflorescence typically shows up better on darker concrete and occurs when the salts and other materials in the concrete make their way to the surface.
So you have two.
Unless you take every step to keep the soil surrounding the walls as dry as possible those ugly stains will just keep coming back.
Rinse off the wall with fresh clean water.
Apply undiluted white vinegar to the entire mineral deposit you are attempting to remove and allow the stain to soak for approximately 20 minutes.
Therefore the first step to correct any type of basement wall stain problem is to provide adequate foundation drainage in order to minimize the water infiltration.
When groundwater consistently infiltrates the porous concrete walls through capillary action wall stains and related problems can occur.