Bas Pluim wrote:

My basement has some mold growing on the walls. It's not too bad, only in
one area where the water pump sits. I don't think there is any water coming
in from the outside (there is another utility area on the other side of this
wall, which is mold free). I improved the ventilation, took care of some
condensation problems (the most likely culprit), and added a dehumidifier,
so I'm read to tackle what will hopefully the last of the mold.

There are plenty of posts (and answers!) on mold removal, but not on what
constitutes "clean".

I've scrubbed the walls down with Chlorox and a striff bristle brush. Gone
over it several times. The walls are cement block, painted white. The paint
has held up well, no flaking. The appearance of the blocks has improved, but
there are still a brownish/ blackish stains on the blocks, especially in and
around the mortar lines. Do I need to keep scrubbing it until it's ALL gone,
or is that overkill? Would a wire brush help?

Thanks!


Overkill. You could use a toothbrush with straight bleach, being
careful not to splatter on yourself, if you want overkill. Some mildew
leaves a stain, which I would expect to be more permanent on latex
paint. Folks panic at mention of the word "mold", but if it looks
clean, it probably is clean. There might be more moisture on the mortar
if some is from seepage, but any significant amount of seepage ought to
make the paint peel.