Leak underneath bathroom sink

Baggypuss

I just bought my first home. Initially I had no problem using bathroom sink as I did not push internal plug whilst washing hands. However, the first time I used plug to fill basin with water and mild detergent, I found water leaking from drainage apparatus as shown below. Not sure whether it started leaking whilst plug was on or off. 

Sorry for terminology as not a DIY person.
Was told by a friend that drainage might be blocked and need to pour down some unblocker liquid.

Any advice would be appreciated

WIAWSNB

Baggypuss said:

I just bought my first home. Initially I had no problem using bathroom sink as I did not push internal plug whilst washing hands. However, the first time I used plug to fill basin with water and mild detergent, I found water leaking from drainage apparatus as shown below. Not sure whether it started leaking whilst plug was on or off. 
Sorry for terminology as not a DIY person.

Was told by a friend that drainage might be blocked and need to 

pour down some unblocker liquid. Any advice would be appreciated

Hi.

Step one is to ID where - exactly - the water is coming from.

So wipe it all up, and refill basin as before. Shine a torch at the plumbing and undersink, and see where the leak is.

I presume that basin has an overflow? And this is built in to the ceramic moulding? Did the water reach that level?

A blockage doesn't usually cause a leak. 

Baggypuss

I will have a look

ButterCheese

First off - don't pour any chemicals down there yet.  Chemicals can damage anything they contact i.e. hands, shelves. And you don't want all of that pouring out when you do the next step:

It looks like it has already been bodged.  The top (white) screw ring is what holds the pipe to the actual sink outlet.  CAn you unscrew that and take the pipe off?  You might also need to unscrew the other part at the bottom of the S bend to take that whole section out.  Make sure you have a bowl underneath and some old towels handy.

You will now have the sink/plug outlet which looks to have been bodged up with some sort of filler/sealer.  If you now run a bit of water into the sink (making sure you have a bowl below) it should come out of the middle of the outlet, not around the sides.  I suspect that the outer screw part that holds in the sink outlet has been overtightened or cross-threaded, so it's not sealing properly. If you are confident enough, try buying a new sink outlet and fit yourself (look up youtube how to's), or it's a simple job for a plumber

Baggypuss

Filled with water not up to overfill hole. Even with plug on, water leaking from where silicone ring is.

Baggypuss

Above black ring

stuart45

The retaining nut that you've got your hand on should be tightened up to squeeze the washer and create a seal.

Baggypuss

I have removed p trap and tighted black ring (I.e. retainer nut)?

Rodders53

That probably all just needs undoing and re-making properly after a good clean up.

Looks like plumbers mait https://www.screwfix.com/p/evo-stik-plumber-s-mait-750g/14477 has been used at the topto my eyes... but too much and that black nut you are holding should be screwed up tight (by hand) to the sink waste... The difficult bit is to stop the waste top turning while tightening up!

Some wastes are made of brass and chrome others can be made of a flimsy cast alloy.  The best sink wastes have brass nuts rather than nylon/plastic.  The thread on plastic nuts can be fairly easily stripped.

Some people use a 'basin mate' Basin Mate 1 1/4 | Toolstation where a rubber wedge is fitted and compressed via the nut... (the pic of it is 'upside down' to how it fits the waste).

The plastic P-trap may be missing a rubber sealing washer as shown here  Viva Swivel P Trap 75mm Water Seal 1 1/4" | Toolstation The washers can be obtained as spares.

Baggypuss

retainer nut is split

stuart45

Baggypuss said:

I have removed p trap and tighted black ring (I.e. retainer nut)?

That's how it should be. See if it still leaks. If it does you'll need to take the waste off and start again. New ones have a foam washer that goes on top of the basin, but most plumbers sling it and use silicone.