Eight years ago I bought a new build Bovis home. Within four months it flooded. I had to pay for a surveyor as both Bovis and the NHBC refused to consider the problem. He determined that the builders had failed to properly address the drainage behind the house where there is a steep bank. Bovis responded by installing an aco drain which simply discharged to run off. The house has flooded twice since then with the latest leaving the house inundated for over five months. Bovis sent out a manager but refuse to comment or release his report. The NHBC says it was due to weather. A surveyor now reports that there has been a serious failure of build with the builders not addressing the issue of ground water. He has recommended the garage floor be completely removed and a dpm installed as should have been. The NHBC and Bovis have ignored this finding. I now have to instruct a drainage expert to review the complete lack of drainage to the rear of the house. I am not alone with this matter as houses in the area are progressively flooding. What can I do now?