ST 30 and ST 35 Greywater Tanks

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TodOneD

Member
Joined
Mar 23, 2025
Messages
10
Location
New Mexico, United States
Is there a difference in Swift Trawlers imported to the US with regards to grey water tanks? If one wanted to spend a fair amount of time at anchor or on moorings, I would think having shower and sinks fill up your black water tank would be a pretty big limiting factor. If regulations are different for discharging black water and grey water, I would think that having a grey water tank would be quite useful.

-Tod (newbie)
 
Currently there are very few places in the USA that limit grey water discharge. My trawler was setup to have either grey discharged over the side or dumped into the black water tank. The one place I needed to use it was Isle Royale national park in Lake Superior. Personally I'd much prefer a larger black water tank than separate black and grey water tanks. When you don't need to retain grey water, it would be nice to have a larger black water tank.

Ted
 
Ted,

Totally agree. Our fwd black water tank is 204 gal capacity. Toilet Shower and head sink used to go into it. Now shower pumps overboard. Sink still goes into tank. We can go for a LONG time on that!

Aft holding tank is 140 gallons, similar deal, Toilet, Shower, Sink, but with the addition of washing machine go into it. Washing machine is 13 gallons/load. we re-plumbed to pump shower overboard, and plan on plumbing the washing machine for overboard as well eventually . . .

Easy to design in large holding tanks, but much more difficult to retro fit older boats. . . .

One frustration is that now some municipalities and/or states are adding legislation that requires holding tanks to be pumped out periodically, time limits vary, but every 10 days appears to be a common time limit. No specific requirements for documenting the pump-outs either. Some say you must have receipts, some just say "records". Personally, we just note in our underway log book if we pump out >legal distance offshore (no receipts), and I say "legal distance" because in some areas, the legal distance is > 3 miles. In the case of pump out boats that come to us, we just note in our last "underway" date logsheet, under "Black Water tank status" the date pumped out.

For us, a pump out every 10 days is ludicrous, especially if we have to pay for it, even in the 140 gallon aft tank. Say we do 5 laundry loads at 13 gallons/load (one every TWO days) that only adds 65 gallons, and sink and toilet, even if we used the aft head exclusively, which we don't, probably not more than another 40 gallons or so, and that's being REALLY over the top on usage, we'd only have used 105 gallons aft, and we'd still have 35 gallons to go aft, which is more than the size of most peoples black water holding tanks! That doesn't even take into account the 204 gallons unused fwd.

It's no wonder we have so many screwed up laws, when lawmakers aren't required to be knowledgeable about anything they pass laws about. . . . :nonono:
 
Wow, 204 gallon capacity! On the Swift Trawler 30 it is 23 gallons. Thanks for the info. Curious if owners of newer Swift Tralwers have grey water tanks, and if shower or sink has option to bypass any tank...
 
I saw a sign this spring in Pittsburg CA that stated it was now illegal to dump black or grey water anywhere in the delta. I was so taken aback that I thought about snapping a picture and posting it here. There are so few boats designed to hold grey water, it could not be enforceable at all. Our 17 gallon black water tank could never hold the sink and shower discharges. I haven’t seen that sign anywhere else in the Delta, so I am assuming Docktopus is grandfathered in.
 
Grey drains overboard.
I have a Benneteau flyer 12 built in Europe with 25 & 15 gallon black water tanks and a 13 gallon gray water tank. The sinks, showers and an a/c condensate lines all drain into my gray water tank. Beneteau designed the gray water tank to theoretically drain itself each time you turn the boat DC power off and back on however that doesn’t work so we’re stuck with manually draining the grey water tank. Has anyone found a marine electrician in the Jacksonville area knowledgeable about Beneteau systems?

Regards Eastern Shore
 
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