Marine Sanitation Device Standard
Federal law prohibits recreational and commercial vessels from discharging raw or inadequately treated sewage into U.S. waters. The Marine Sanitation Device (MSD) Standard — codified at 40 CFR Part 140 — specifies what treatment equipment vessels must carry, sets discharge performance standards, and establishes a process by which states can designate waters as No-Discharge Zones where overboard discharge of any sewage, treated or not, is completely banned.
Legal Authority
- 33 U.S.C. § 1322 — Clean Water Act § 312; establishes federal standards for marine sanitation devices (MSDs) on vessels; authorizes EPA to set performance standards for MSDs and the Coast Guard to establish design and construction standards and certification procedures; allows states to petition EPA to prohibit discharge of treated sewage in designated "no-discharge zones"
- 33 CFR Part 159 — Coast Guard implementing regulation; establishes Type I, II, and III MSD certification standards and testing procedures; determines which vessel types must have certified MSDs
- 40 CFR Part 140 — EPA marine sanitation device effluent standards; sets allowable coliform limits for treated sewage discharge from Type I and Type II MSDs
Key Mechanics
The MSD regulatory framework applies to vessels with installed toilet facilities operating on navigable U.S. waters. The framework creates three MSD types based on treatment level: Type I (macerator-chlorinator or equivalent) treats sewage to 1,000 coliform per 100 mL — allowable for discharge in most waters; Type II (biological or chemical treatment) achieves 200 coliform per 100 mL — required for larger vessels in some states; Type III (holding tank) holds sewage with no discharge until pumped out at a shore-based facility. Which type is required depends on vessel length (Type I or II required on vessels 65 feet and over in some contexts) and geographic zone. States may petition EPA to prohibit discharge of treated MSD effluent in designated "no-discharge zones" (NDZs) — waters where only Type III (no-discharge) is permitted; as of 2025, there are NDZs covering Great Lakes waters, many New England lakes and bays, and portions of the Chesapeake Bay. All MSDs must be certified by the Coast Guard before installation; uncertified devices are illegal. Vessels in NDZs must either use a Type III device (holding tank) or demonstrate that heads are sealed while in the NDZ. Marina pump-out stations are required by CWA § 312 to be available in NDZ-designated areas.
Current Rule (2026)
| Parameter | Value |
|---|---|
| Citation | 40 CFR Part 140 |
| Issuing agency | EPA (performance standards); U.S. Coast Guard (certification and equipment standards at 33 CFR Part 159) |
| Statutory authority | 33 U.S.C. § 1322 (Clean Water Act § 312) |
| Applies to | All vessels with an installed MSD on U.S. waters |
| Exemption | Vessels not equipped with an MSD are not required to install one by this rule; only vessels with toilets |
| National security exemption | Vessels owned/operated by DoD unless the Secretary of Defense finds compliance not in the national security interest |
What This Rule Does
40 CFR Part 140 sets federal performance standards for marine sanitation devices — the toilets and sewage treatment systems aboard boats. The rule does not require every vessel to install a toilet, but any vessel that has a toilet must have an approved MSD that meets EPA's standards. The U.S. Coast Guard certifies MSDs under 33 CFR Part 159 and enforces MSD requirements aboard vessels.
MSDs come in three certified types, with progressively stricter treatment requirements:
- Type I — treats sewage to produce effluent with no more than 1,000 fecal coliform bacteria per 100 ml and no visible floating solids; permissible discharge in most open waters
- Type II — higher treatment standard, producing effluent with no more than 200 fecal coliform per 100 ml and no more than 150 mg/L total suspended solids; required in some sensitive waters and no-discharge zones may require Type III
- Type III — holding tanks that retain sewage onboard with no discharge; required in any federally designated no-discharge zone; waste is pumped out at a marina pump-out station
Key Provisions
- § 140.1 — Definitions: "marine sanitation device" means any equipment for installation onboard a vessel to receive, retain, treat, or discharge sewage; "vessel" covers every watercraft capable of being used as a means of transportation on waters of the U.S.; "existing vessel" was constructed before January 30, 1975; "new vessel" after that date
- § 140.2 — Scope: applies only to vessels with an installed MSD; does not require installation on vessels lacking them; exempts military vessels unless DoD determines compliance is in national security interest
- § 140.3 — Performance standard: in freshwater lakes, reservoirs, and rivers not navigable by interstate vessels, MSDs must produce no discharge; in other waters, Type I or II MSDs meeting fecal coliform and suspended solids limits are permissible; the standard varies by water type to protect drinking water sources and sensitive aquatic areas
- § 140.4 — Complete prohibition (no-discharge zones): states can completely ban overboard discharge of any sewage — even treated effluent — by applying to EPA under CWA § 312(f)(3); EPA must grant the designation if the state demonstrates that adequate pump-out facilities are reasonably available; once designated, vessels in that zone must hold all sewage in Type III devices until they leave the zone; major no-discharge zones include Puget Sound (WA), most of Florida's waters, Lake Tahoe (NV/CA), the Great Lakes, and portions of the Chesapeake Bay
- § 140.5 — Analytical procedures: testing MSD effluent quality uses the methods in 40 CFR Part 136 (EPA's standard test procedures for water pollutant analysis)
How It Affects You
Recreational boaters need to know whether their cruising area is a no-discharge zone. If you're boating in Puget Sound, Chesapeake Bay, or Florida's inland waters, your holding tank must stay closed — you can't pump out at sea, only at a marina pump-out station. Outside no-discharge zones, a Type I or II MSD is sufficient in most saltwater and larger navigable rivers. Violation of the no-discharge rule can result in CWA enforcement — the Coast Guard and state marine patrol agencies actively cite violations.
Marina operators in no-discharge zones are expected to provide pump-out facilities; states designating no-discharge zones must demonstrate pump-out availability as part of the application to EPA.
Vessel manufacturers and designers must equip new boats with MSDs certified by the Coast Guard that meet EPA's performance standards; uncertified marine toilets cannot legally be installed on new vessels.
Statutory Authority
This rule implements:
- 33 U.S.C. § 1322 — CWA § 312: specifically authorizes EPA to set marine sanitation device standards; authorizes Coast Guard to certify devices; authorizes EPA to designate no-discharge zones upon state application; prohibits marine sanitation devices that don't meet EPA standards in new vessels
Recent Rulemakings
- 77 FR 11411 (Feb. 27, 2012) — amendment clarifying no-discharge zone application procedures
- 67 FR 35743 (May 20, 2002) — updated definitions and procedures for state no-discharge zone designations
- No major amendments in the last 5 years; the basic MSD standard framework has been stable since 1975
Pending Action
No pending federal rulemaking under 40 CFR Part 140 as of 2026.