33 CFR 155.350: Oily bilge and ballast discharges on small ships
Last reviewed: October 14, 2026
This section covers oily mixtures from bilges and fuel oil tank ballast on oceangoing ships of less than 400 gross tons. A ship must either retain all oily mixtures and be able to discharge them to a reception facility, or have approved oily-water separating equipment. Barges without an installed bilge pumping system for discharge into the sea, and drilling rigs and other platforms, are excluded.
Applies toOceangoing ships of less than 400 gross tons, except a barge not equipped with an installed bilge pumping system for discharge into the sea and a fixed or floating drilling rig or other platform.
What it says
No person may operate an oceangoing ship of less than 400 gross tons unless it meets one of the equipment options in paragraph (a).
33 CFR 155.350(a)“No person may operate an oceangoing ship of less than 400 gross tons, unless it either:”
One option is that the ship has the capacity to retain all oily mixtures on board and is equipped to discharge them to a reception facility.
33 CFR 155.350(a)(1)“Has the capacity to retain on board all oily mixtures and is equipped to discharge these oily mixtures to a reception facility;”
The other option is that the ship has approved oily-water separating equipment for oily mixtures from bilges or fuel oil tank ballast, and discharges into the sea according to § 151.10 of this chapter.
33 CFR 155.350(a)(2)“Has approved oily-water separating equipment for processing oily mixtures from bilges or fuel oil tank ballast and discharges into the sea according to § 151.10 of this chapter.”
Equipment installed after 2004 must meet current standards in 46 CFR part 162, subpart 162.050 to be approved, unless it is installed on a ship constructed before 2005 and meeting those standards would be unreasonable or impracticable.
33 CFR 155.350(a)(3)“unless the equipment is installed on a ship constructed before 2005 and it would be unreasonable or impracticable to meet those current standards.”
A ship entering international service for the first time since 2004 must comply by the date of its initial survey before it receives its International Oil Pollution Prevention (IOPP) certificate.
33 CFR 155.350(a)(3)(i)“must comply with the requirements of paragraph (a)(3) of this section by the date of its initial survey prior to receiving its International Oil Pollution Prevention (IOPP) certificate.”
Any other ship must comply by the date of its first drydock after October 13, 2009.
33 CFR 155.350(a)(3)(ii)“must comply with the requirements of paragraph (a)(3) of this section by the date of the ship's first drydock after October 13, 2009.”
An oceangoing ship of less than 400 gross tons may retain all oily mixtures in its bilges, and it does not need an oil residue (sludge) tank.
33 CFR 155.350(b)“may retain all oily mixtures on board in the ship's bilges. An oil residue (sludge) tank is not required.”
Common questions
Does a small oceangoing ship need an oil residue tank?
No. An oceangoing ship of less than 400 gross tons may keep all oily mixtures in its bilges, and an oil residue (sludge) tank is not required.
“An oil residue (sludge) tank is not required.”
Does 33 CFR 155.350 apply to barges?
It does not apply to a barge that has no installed bilge pumping system for discharge into the sea.
“This section does not apply to a barge that is not equipped with an installed bilge pumping system for discharge into the sea.”
Does 33 CFR 155.350 apply to drilling rigs?
No. The section does not apply to a fixed or floating drilling rig or other platform.
“This section does not apply to a fixed or floating drilling rig or other platform.”
The text of 33 CFR 155.350
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less than 400 gross tons
(a) No person may operate an oceangoing ship of less than 400 gross tons, unless it either:
(1) Has the capacity to retain on board all oily mixtures and is equipped to discharge these oily mixtures to a reception facility; or
(2) Has approved oily-water separating equipment for processing oily mixtures from bilges or fuel oil tank ballast and discharges into the sea according to § 151.10 of this chapter.
(3) For equipment installed after 2004 to be approved under paragraph (a)(2) of this section, it must meet current standards in 46 CFR part 162, subpart 162.050 by the date set forth in paragraphs (a)(3)(i) and (a)(3)(ii) of this section, unless the equipment is installed on a ship constructed before 2005 and it would be unreasonable or impracticable to meet those current standards.
(i) A ship entering international service for the first time since 2004, must comply with the requirements of paragraph (a)(3) of this section by the date of its initial survey prior to receiving its International Oil Pollution Prevention (IOPP) certificate.
(ii) Any ship, other than a ship described in paragraph (a)(3)(i) of this section, must comply with the requirements of paragraph (a)(3) of this section by the date of the ship's first drydock after October 13, 2009.
(b) An oceangoing ship of less than 400 gross tons may retain all oily mixtures on board in the ship's bilges. An oil residue (sludge) tank is not required.
(c) This section does not apply to a barge that is not equipped with an installed bilge pumping system for discharge into the sea.
(d) This section does not apply to a fixed or floating drilling rig or other platform.
Sections it refers to
- 33 CFR 151.10
- 46 CFR part 162, subpart 162.050
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.