Holding tank query.

[adrianm]

My (part finished) boat has tanks in the aft-cabin that are marked as black water on the plans and tanks forward that are marked as grey water. Between the two is the engine room with very little room to run pipes.

My question is could I use them as combined grey/black water so I don't have to route pipes through the engine room (both have macerator outlet pumps and deck discharge points) or would that be breaching some EU regulation?

Thanks in advance for any advice.

 

[Evadne]

Which country of the EU are you concerned about? Contrary to popular belief the EU does not regulate what goes on in member states, local laws and regulations apply. The UK has no regulations that affect the average yacht, although many others do and inland waterways are a different kettle of fish, but as far as I can see there are no regulations on how big such a tank should be or the differentiation between grey and black water while it's on board. The RYA has some info. on their website.

 

[Norman_E]

My concern would not be regulation, but the mixing of grey water and toilet waste, because there is usually nothing to stop the contents of an over filled grey water tank backing up to the galley sink. That becomes a real health concern if it is mixed with sewage. Even if you fit non-return valves could you really trust them if the boat heels too far in a gust?

 

[Ships_Cat]

As pointed out by another one NEVER puts grey water into black water tanks because of the risk of probable back contamination of other bathroom and galley facilities.

John

 

[adrianm]

That's one of those blindingly obvious things that I didn't think about; what happens when the tank is full.

Looks like I will have to find someway of routing all the pipework through the engine room. Typically the clearest part is the furthest point away from the tanks.

Thanks for the advice.

 

[nedmin]

If you are building the boat or fitting out yourself why dont you do as my Pedro cruiser, it has a venturi tube coming out the hull at about 45 deg. pointing to the stern, of approx.2inch dia. with a seacock inboard, this is connected to the sole holding tank, when travelling above 4knts the tank level drops about a foot, when you stop it refills, continuosly flushing the tank out. If you are in a marina you could close the seacock to prevent discharge altho. I never bother,when ducks wear nappies I may do. there is a pumpout deck fitting and a level gauge.

 

[Stemar]

I can see the need for a holding tank for black water - if I could figure out a cost-effective way of putting one in Jissel, I would - but where, apart perhaps from a small lake, would grey water discharge be a problem?

Surely the worst that's likely to contain is a bit of washing up liquid and some congealed gravy?

 

[Norman_E]

Quote " but where, apart perhaps from a small lake, would grey water discharge be a problem? "

This problem is coming to a waterway near you. The environmentalists are now saying that such things as detergents in grey water are more harmful to the marine environment that human waste. Probably true, but the end result is that compulsory toilet holding tanks will be followed by compulsion in regard to grey water discharge. Whilst it may remain acceptable to discharge toilet waste away from land, it is quite possible that only onshore pump out will be acceptable for grey water at a future date in places like the Med.

 

[chrisc]

bit of washing up liquid and some congealed gravy? ----------
Which are precisely the things which create the greatest ecological dangers !
discharging washing up liquid is illegal in some countries-toilet waste is more of a cosmetic problem.

 

[nedmin]

One of the biggest probs with holding tanks are some narrow boat owners, they add formaldehyde to the tank to stop it smelling then they discharge by macerator when its full.which is lethal to fish. A crap a day does no one any harm, If you want to stop detergent getting into rivers etc the only way is to ban washing machines as most sewage works discharge into rivers and canals.I moor at night on the none tidal Trent and the weir is full of foam,usually much worse early morning,do they discharge more at night!!??