Abstract: Apparatus for producing a waterfall at the edge of a swimming pool, spa or pond, the apparatus including a generally cylindrical reservoir in the water circulation system path, with at least one water discharge metering rod on the axial centerline of the reservoir, configured for directing water in a first direction diametrically opposite an elongate discharge plenum having a second plenum in fluid flow communication therewith for discharging the water into the pool through a sidewall thereof. The apparatus is placed inside the wall on the side of the pool and produces a smooth even sheet of water which is directed away from the side of the pool. The metering rods are constructed for adjusting pressure along the axial length thereof to cause the water pressure inside of the unit to be maintained evenly across its length thereby directing the water out through the throat of the discharge plenum.