Sea-Dog Black Waste Deck Fill Replacement Cap – 1-1/4" NPSM (357018)
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The Sea-Dog 357018 Black Waste Deck Fill Replacement Cap is a color-coded replacement cap for Sea-Dog 357010 series waste deck fill fittings. The black cap designates the waste (holding tank) fill or pump-out point — a critical safety and sanitation convention on multi-fill boats to prevent accidental cross-connection with fuel or water fills. The 1-1/4" x 11-1/2 NPSM straight thread provides a secure, odor-sealing closure at the deck fitting.
Key Features
- Black color coding — designates waste/holding tank deck fitting per marine convention
- Thread: 1-1/4" x 11-1/2 NPSM straight
- Designed for Sea-Dog 357010 series waste deck fill fittings
- Replacement cap only — fill body sold separately
- SKU: 354-3570181
Best Use Case
Use this cap to replace a missing or damaged cap on a Sea-Dog 357010 series waste deck fitting. A missing waste cap is both a sanitation and odor issue — replace promptly to maintain a proper seal on the holding tank pump-out connection. On boats with multiple deck fills, maintaining correct color-coded caps (red = gas, green = diesel, black = waste, blue = water) is essential for safe and compliant operation.
Parts Desk Insights
This is a waste (black) cap only — confirm your fill body is the Sea-Dog 357010 series and uses 1-1/4" x 11-1/2 NPSM straight thread before ordering. For the matching color-coded caps in this series, see the Sea-Dog Red Gas Deck Fill Cap (357015) and the Sea-Dog Green Diesel Deck Fill Cap (357016). For a complete deck fill assembly, see the Sea-Dog 3570301 Gas Deck Fill with Keyless Cap.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.