im buying a house from a developement company y dont they warranty my basement waterproof?

they fixed everything in the house all new electrical system,heating system,plumbing system, and main roof but when it comes to the basement they fixed the water problem but wouldnt put it under warranty like they did the other things they fixed why is dat?

View this post on my blog: http://madeinhome.info/im-buying-a-house-from-a-developement-company-y-dont-they-warranty-my-basement-waterproof