I REFER to the letter headlined, ''Inconvenience over toilets'' (South China Morning Post, July 27), regarding alleged problems with flush water supply in Ap Lei Chau.

We cannot investigate this unless we have more precise details and would be grateful if the correspondent, ''Name and Address Supplied'' would contact Mr C. K. Wong, at telephone number 880 2544.

K. W. LAM Chief Engineer/ Hong Kong and Islands Water Supplies Department