Pistapaug Pond a 136-acre municipal reservoir for the town of Wallingford, and public access is prohibited. The pond is largely surrounded by forest with some grassy areas along the southwest shore. A steep trap rock ridge runs along the eastern side of the pond, dropping steeply into the water with an extensive talus slope. The lake bottom is largely gravel, with some sand at the northern and southern ends.

Aquatic plants grew abundantly around the pond's edges at the time of our June 2005 survey. The most abundant of these was small pondweed (Potamogeton pusillus) which occurred in large patches all around the pond and was particularly abundant in a broad shallow water area at the pond’s southern end. Patches of other pondweeds, including variable pondweed (P. gramineus), Illinois pondweed (P. illinoensis), and snailseed pondweed (P. bicupulatus), also were recorded in this area, as were slender naiad (Najas flexilis), water smartweed (Polygonum amphibium) and the invasive Eurasian watermilfoil (Myriophyllum spicatum).

Eurasian watermilfoil also grew along the eastern shore except where the pond's bottom dropped steeply. Small patches of Illinois pondweed also were observed along the eastern shore, and isolated patches of coontail (Ceratophyllum demersum), slender naiad and arrowhead (Sagittaria species) were recorded. The northern end of the lake supported scattered plants of small pondweed, Illinois pondweed, and Eurasian watermilfoil.

Plants were more abundant along the western shore, where small pondweed and Eurasian watermilfoil grew in wide, dense bands. A large area near the southwestern shore supported abundant growth of snailseed pondweed. Also in this area were patches of Illinois pondweed, slender naiad, yellow water lily (Nuphar variegata), and water smartweed.