EPA's Vessel General Permit and Small Vessel General

waters (Appendix G, VGP).
Non-Oily Machinery Wastewater. Non-oily machinery wastewater systems contain water that
does not come into contact with machinery that uses oil. Examples include distillers, condensate
drains, pump drains, potable water tank overflows and leaks from propulsion shaft seals. These
wastewater systems may result in discharges of various pollutants into waters of the U.S.
For vessels covered under the VGP, EPA requires non-oily machinery wastewater to be free
from oils (in quantities that may be harmful pursuant to 40 CFR Part 110) and any additives that
are toxic or bioaccumulative in nature, if discharged directly overboard. They permit non-oily
machinery wastewater to be drained to the bilge.
Refrigeration and Air Condensate Discharge. Condensation from refrigeration or air condition
systems may discharge into waters of the U.S. and may contain detergents, metals and other
pollutants.
For vessels covered under the VGP, EPA prohibits the discharge of refrigeration and air
condensate, if it had come into contact with oily or toxic materials. They permit the discharge of
refrigeration and air conditioning condensate that is collected and plumbed for internal recycling
(e.g., recycled as “technical water”) which has commingled with oily water if the commingled
discharge meets the discharge requirements for oily mixtures and oily water separator effluent.
Seawater Cooling Overboard Discharge. Seawater cooling systems circulate ambient water
through an enclosed system and may be discharged into waters of the U.S. These discharges
may contain hydraulic fluid, lubricating oil and metals and may also be of higher than ambient
temperature. These discharges include non-contact engine cooling water; hydraulic system
cooling water, refrigeration cooling water.
For vessels covered under the VGP, EPA requires vessel owner/operators to maintain all piping
and seawater cooling systems must meet the requirements as described below.
Seawater Piping Biofouling Prevention. Seawater cooling systems may contain anti-fouling
compounds. These compounds may be discharged into waters of the U.S.
For vessels covered under the VGP, EPA requires vessel owner/operators to use seawater piping
biofouling chemicals subject to FIFRA registration (see 40 CFR § 152.15) in accordance with
their FIFRA label. They prohibit the discharge of pesticides or chemicals banned for use in the
U.S. They require vessel owner/operators to use the minimum amount of biofouling chemicals
needed to keep fouling under control and discharges containing active agents to contain as little
chlorine as possible. Vessel owner/operators are required to remove fouling organisms from
seawater piping on a regular basis (though regular is not defined) and dispose of removed
substances in accordance with local, state, and federal regulations. The EPA prohibits the
discharge of removed fouling organisms into waters of the U.S.
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