http://en.wikipedia.org/wiki/Efflorescence

Scoll down to the Masonry part. It is from water seeping through the cinder blocks and then drying/evaporating, leaving behind these white powdering substances which is natural salts in the water. You do need to remove it before painting/waterproofing etc.

If you go down to your local hardware store, they will carry various products to deal with this or you buy Muriatic acid itself and dilute it as per instructions. Drylok is one namebrand and is carried by Lowes. And of course, there are others..

jay

lorislines,

jayh is absolutely right in his response. But...I would be concerned about the water/moisture seeping through the cinder block. Waterproofing should be on the outside and done before backfilling so that you don't get any seepage. You can get products to seal the inside but they are not usually that good. You really have to stop the moisture on the outside. Get in contact with your builder and quiz him about it. You must have some kind of home warranty. What do you think jay?

Thank's so much to both of you. I do know that a black waterproofing material was applied on the outside blocks. It is surprising though that moisture is seeping through. I think you're right in that we need to talk to the Mason's who completed the job. Again, I appreciate the help.

ahh, went back and reread the original post. Didn't see that it is a new home. Most certainly get back to the contractor/masons and talk to them about it. Maybe take a photo of it for proof (you never know these days).

Jay

It isn't the masons fault. He did his job. There is a material that one can put around a new build foundation that actually wraps the walls to prevent moisture seepage. I have seen it, Unfortunately I don't know what name it goes by

It's called bubble wrap, for new builds