Marinas & Grey Water Holding Tanks.

[Pelagic]

Probably a grey area depending on region and regulations, but now that I am back living onboard at Subic Marina I am amazed at the stench from full grey water holding tanks being pumped out in the evenings.

Everybody uses the excellent shore side toilets, but all the new multis hold their shower and Galley water for a few days, then pump out copious amounts that has not aged well!

Before my refit, I had the same and the showers/ sinks would all pump into holding tank that with 5 onboard wold be full in about 6 days.
You could definately smell it!

So I decided to put Y-Valves in and divert to direct discharge.

Now, the small amount of "fresh" shower water pumps quietly into the marina, with no stench at all.... I like it!

Another plus is that I moved the 2 Whale 320 pumps to the engine room where I have a bildge pump manifold.

One of them now has a second 3/4" suction hose with a Y- valve that goes into my deep engine well.
When washing down, it is a perfect wet vacumn.

Why hold grey water for days, rather than direct discharge, if allowed?

[Allied39]

The solution to pollution is dilution.

[Reo Baird]

At least on my boat, the staterooms are below waterline enough that a grey water holding tank with sump is required for drainage. That's probably why not direct discharge? Mine has a float switch and pumps out automatically though and does not hold water for days.

[valhalla360]

Where are you? In the vast majority of the world, no one has gray water tanks. It just goes straight out a thru hull. Positive side with no fermenting, no odor.

But yes, gray water that is stored typically smells worse than black water (both are commonly stored in RV's). Not fully sure why it smells worse...maybe adding the soap to the food particles does something.

[Pelagic]

Originally Posted by Reo Baird

At least on my boat, the staterooms are below waterline enough that a grey water holding tank with sump is required for drainage. That's probably why not direct discharge? Mine has a float switch and pumps out automatically though and does not hold water for days.

Same here, the Fwd and Aft Shower/Sink drains are below the waterline and were pumped to holding tank under galley.

The Galley sink can flow directly overboard, but also has Y-valve to holding tank. It is always on direct overboard.

All I did was disconnect the hoses from fore and aft drains to holding tank.
Re-locate the diaphragm pumps and suction filters into the engine room, with a large anti siphon loop before discharge at waterline.

Now both grey pumps and small bildge pump join downstream in a vertical discharge tree along with the brine line from the water maker.

Yesterday I flushed out and changed the main engine and generator freshwater coolants dumping a lot of water into my normally dry steel bilge.

With an additional screened 3/4 hose and Y-conection on suction side of the pump, I got to test my "bilge vacumn" and got the water down to a tiny 1/2" part fwd.

It took a day to change, but I am happy now that the holding tank can stay clean and empty, unless I need to use it on rare occasions.

As for Toilet, if we cannot direct discharge at an anchorage, we dont stay there. In marinas we use shore toilets.

[Pelagic]

Originally Posted by valhalla360

Where are you? In the vast majority of the world, no one has gray water tanks. It just goes straight out a thru hull. Positive side with no fermenting, no odor.

But yes, gray water that is stored typically smells worse than black water (both are commonly stored in RV's). Not fully sure why it smells worse...maybe adding the soap to the food particles does something.

To clarify, my grey and black (toilets) water was plumbed into same holding tank.
As I never pump sh*t into that tank in Asia, it was only used for Grey shower water

[valhalla360]

Originally Posted by Pelagic

To clarify, my grey and black (toilets) water was plumbed into same holding tank.
As I never pump sh*t into that tank in Asia, it was only used for Grey shower water

Is that a local requirement or just an odd design?

[Pelagic]

Originally Posted by valhalla360

Is that a local requirement or just an odd design?

I really don't know. That is how the boat came with the below water drains being pumped into the same holding tank for the two toilets.
It has it's pros and cons and I guess would pass the tightest environmental standard to hold both grey and black
...but in practice, direct discharge of small amounts at anchor makes more sense in uncrowded areas

[sailorboy1]

Originally Posted by Pelagic

Why hold grey water for days, rather than direct discharge, if allowed?

good question

I only have 1 grey water sump and it doesn't get water very often and I have to once in a while flush and bleach it. I'm thinking of just disconnecting it and letting toi drain to the bilge as that's less trouble to flush/clean.

[wingssail]

Originally Posted by Pelagic

Probably a grey area depending on region and regulations, but now that I am back living onboard at Subic Marina I am amazed at the stench from full grey water holding tanks being pumped out in the evenings.

Are you sure the stench doesn't come from the Pamulaklakin River and the drainage channel, both of which empty directly into the bay in the vicinity of the Subic Bay Yacht Club?

When I was there in 2006 it was was pretty foul when all the folks in Olongopo got home from work and flushed their toilets.