Placing Drainpipe To the Editor: With regard to the question "Orienting a Foundation Drain" (On the House, 7/94), I would like to add a couple of items: Locating the holes in the drain in the 4 o'clock/8 o'clock position is done not only to allow groundwater to rise into the drain and be quickly disposed of, but also to minimize the chance that fines filtering into the drain system from above will enter the drain and possibly block it over time. In fact, drains installed with too much slope can actually pull sand and other fines into the system. Mr. Marsh's reminder that the stone is part of the drainage system is a point well taken. Taking a