The ornamental design for a vent for septic system, as shown and described.
This Application incorporates and claims the benefit of U.S. Design application Ser. No. 29/155,625, filed Feb. 15, 2002, by William M. Traut et al., entitled Vent For Septic System.
FIG. 1 is a side elevational view of a vent for septic system according to the invention with a door design appearing on one side, but not appearing on the remaining similar sides;
FIG. 2 is an exploded side elevational view thereof; and,
FIG. 3 is an exploded side bottom perspective view thereof.