HW tap just a dribble

[Kevin1908]

The HW tap in the bathroom basin has been reduced to a dribble. This happened overnight so was not a long term deterioration. I took the tap out to inspect it and found nothing wrong so it must be a blockage but where and how
Can the stop valve t blocked

 

[ShaunCorbs]

have you tried taking the spindle out (tap top/head) and putting your hand over where it used to go and turn the water back on (slowly) , does it flow full through the tap

if yes your problem is the tap head

if not either your valve is blocked or something else down the line

 

[zzzjim]

Any strainer / economizer fitted at this outlet ?

(Like said -probable ruled out already ..oops )

 

[Best]

Is the tap turning less turns? Usually it is the hot tap on modern taps that does this, although the cold can fail also.
If you take the works apart, - usually a clip on the top, a thread piece that goes into a hexagon shaped piston with tap washer on end and all inclosed inside a brass shell.
The bottom O ring on the piston part can wear & cause water to enter the works. Vaseline or silicone grease on that might help get it working. Sometimes better new works.

 

[Ch4 plumbing]

I would check the airator first if the tap has one, simple stupid check it isn't blocked.