Bath not draining? How to unblock your bath drain

A bath processes a large volume of water in one go, containing shampoo, bubble bath, soap, skin flakes and hair. Because the water only drains away in one surge at the end, dirt has every opportunity to settle in the meantime. Long hairs in particular wrap themselves around the drain mechanism and then catch everything that passes. The result: the bath drains increasingly slowly, until a layer of grey water remains.

How does a bath drain work?

Under most baths there's a so-called waste assembly, also called a waste. It consists of several parts:

• The drain plug in the base. This is often a click plug: you press it to close it and again to open it. On other baths it's a plug that rises when you turn a knob.
• The overflow. The round opening at the top of the bath wall, which drains water if the bath gets too full. With a cable-operated waste, the control knob is also in that overflow.
• The cable or rod. With a cable-operated system, a cable runs from the button in the overflow to the plug in the base. Hair loves to catch on this.
• The trap under the bath. Just like with a washbasin, there is always some water in this to prevent sewer odours. The trap is under or next to the bath, sometimes behind an inspection hatch in the bath panel, sometimes completely built in.

First check where the problem is

If only the bath drains slowly, the blockage is almost always in the plug, the waste set or the trap. Do you notice that the water in the bath or shower comes up when someone flushes the toilet or empties the basin? Then the blockage is further down in the shared drain. You can read more about this in water coming up in the shower.

Unblocking bath drain: step-by-step plan

1. Scoop out the standing water. With a bucket or measuring jug, remove most of the water from the bath. This gives you a better view of what you're doing and reduces spillage.
2. Remove the plug. A click plug can usually be unscrewed anticlockwise while it's open. A plug with cable operation can often be pulled upwards. Wipe off the hair and soap residue, including from the underside and the spring mechanism.
3. Remove hair from the opening. With a plastic hair snake you can pull the hair out of the first section of the drain. With a bath, the largest part of the blockage is often here.
4. Clean the overflow. With many overflows you can unscrew the cover cap. Remove the dirt that has collected behind it.
5. Use a plunger. Cover the overflow well with a wet cloth, otherwise all the pressure will escape through it. Leave a few centimetres of water in the bath and pump vigorously on the drain with a plunger.
6. Accessible trap? Clean it. If the bath has an inspection hatch, check whether you can reach the trap. Lay down towels, place a bowl or flat dish underneath and unscrew the trap by hand. Remove the dirt, check the rubber ring and hand-tighten everything back.
7. Test and check for leaks. Fill the bath a little, pull the plug and check via the access panel that everything stays dry.

If you can't reach the trap because the bath is fully tiled in, do not break open tiles or the panelling yourself. That's the time to call a plumber, who can reach the blockage with a thin snake via the drain opening or the overflow.

What you'd better not do

• Do not pour caustic drain cleaner into the bath. A chemical drain cleaner is caustic and attacks the rubbers and sealant of the waste fitting. An acrylic bath can also become stained or dull. And if the product does not drain away, you are left with a pool of caustic liquid in the tub.
• No boiling water. The waste fitting and the pipes under the bath are almost always plastic. Boiling water can deform PVC over time, resulting in leaks under the bath. Moreover, leaks under a bath often go unnoticed for a long time.
• Don't pull hard on the cable. A cable control is fragile. If the cable breaks or comes loose, the plug won't open or close anymore.
• Don't open the bath panel at random. Without knowing where the trap and pipes run, you'll cause more damage than necessary.

How to prevent it

• Place a hair strainer over the drain, especially if someone in the household has long hair.
• Remove the plug once a month and clean it, even if the bath is still draining well.
• After bathing, briefly rinse the bath with warm water from the shower head, so that soap and bath oil do not remain in the drain.
• Use bath oil and thick bath products sparingly: together with hair, they form a greasy, sticky layer.
• Building a new bathroom? Have an inspection hatch fitted by the trap, so you can access it easily later.

If you also have a separate shower in the same bathroom, also read shower drain blocked. An overview by room can be found in blockage by room.

Is it leaking under the bath?

If you see moisture on the floor after unblocking, a damp patch on the ceiling below or loose sealant, a connection in the waste fitting may be leaking. That is not a job to leave for long. In the article about bathroom leaks you can read what to look out for.

Want to know first what you can do yourself and what's better left alone? Read unblock yourself or call the plumber. For help with a blockage in The Hague, Delft and surrounding areas, see the page about drain unblocking.