TL;DR
Standing water in a shower tray, or a slow basin, is usually hair and soap scum caught in the trap below the plughole. It often clears with a hair-removal tool or a trap clean rather than anything drastic. Avoid chemical cleaners in a shower tray, because they sit in the standing water and can harm the finish. If other fixtures slow down too, the cause is probably further down the system. Request a free quote online if a trap clean does not fix it.
Where shower and bathroom drains block
Nearly all shower and basin blockages start in the trap beneath the plughole. Hair, soap scum and hard-water scale combine there into a solid mat that slows drainage. Compact bathrooms in flats and period terraces often have tight, sharp bends in the waste pipe. As a result, debris has more places to catch before it clears the trap.
Clearing a trap safely
Most shower trays have a removable cover over the trap. Lift it and clear the visible hair by hand, wearing gloves. A flexible plastic hair-removal strip is cheap and easy to find. Push it a short way into the waste and draw it back out to pull the rest of the clog free.
For a basin, the same tool works through the plughole. Alternatively, unscrew the U-bend over a bucket and clean it directly if you can reach it. Afterwards, flush a kettle of hot water through, but not boiling, to clear the soap residue.
Avoid pouring chemical cleaner into a tray that holds standing water. The chemical sits in the tray instead of reaching the trap. It risks the finish and the silicone seal without clearing anything.
Why compact bathrooms block more often
Two things push blockages up in our area. Hard water speeds up scale in traps and waste pipes, which gives hair and soap more to cling to. Our guide on hard water and plumbing explains why this happens along the coast. In addition, many older buildings had bathrooms added later, with narrow pipes and tight bends.
In lower-ground flats, the toilet and shower may drain through a Saniflo or macerator unit, since there is no fall to reach the sewer. The same slow-shower problem can affect homes in Hollingdean area and Southwick area.
When it is the branch, not the trap
If clearing the trap makes no difference, look at the pattern. When the shower drains fine alone but backs up whenever the toilet runs, the blockage has moved past the trap into the shared branch. The fix then needs to go further than the plughole. Treat it as a blocked drain rather than repeating trap cleans that cannot reach it. Our article on blocked drain causes explains how to read the signs.
In a basement bathroom, watch the macerator too. If it hums or trips while the shower drains slowly, the same restriction may cause both faults. Read our guide to Saniflo units that will not flush to compare. A lingering smell is another clue, and our piece on bathroom smells lists the usual causes.
Preventing the next blockage
A cheap plastic hair-catcher over the plughole stops most blockages before they start. It takes seconds to lift out and empty after a shower. Clear visible hair once a week, instead of waiting for the drain to slow. In hard-water areas, an occasional descale of the trap helps too, using a product made for the job rather than a general drain cleaner.
For a pattern of leaks as well as blockages, see our advice on bathroom leaks in flats. Our bathroom plumbing team can help when a simple clean is not enough.
FAQs
Is it safe to use chemical drain cleaner in a shower tray? We would avoid it, particularly with standing water. The chemical tends to sit in the tray, and it can damage the finish and sealant without clearing the blockage.
Why does my shower block more than my sink? Hair is the main reason. A shower collects far more hair than a basin, and with soap scum and scale it forms a denser blockage.
Could a struggling macerator link to a blocked shower? Yes, in lower-ground flats especially. A humming unit and a slow shower can come from one shared restriction.
How often should I clean the trap? There is no fixed rule. Clearing visible hair after each shower and cleaning the trap every few weeks cuts down how often a full blockage builds.
If a trap clean has not fixed it, request a free quote online. We also cover bathroom drains in Worthing area.
