Why your tap timer isn't watering, and how to fix it

June 17, 2025

A tap timer is one of those bits of garden gear you set up once and forget about, which is exactly why it catches people out, because you don't notice it's stopped working until the pots are bone dry, and more often than not the fix is something simple that takes a few minutes to check.

Is it the right kind of timer?

This is the one that trips up a lot of people, so it's worth starting here. A mechanical wind up timer, the kind with a dial you turn to set how long it runs, only turns the water off after the time is up, so you still have to turn it on yourself each time. If you want the garden watered while you're away, you need a battery powered timer that you program with a start time and a run time.

Check the batteries

Flat batteries are the most common reason a battery timer stops, and some timers keep showing the screen for a while after the batteries are too weak to open the valve. Put fresh ones in at the start of every watering season even if the old ones seem fine, and check the program afterwards, because some timers lose their settings when the power goes.

Check the tap and the settings

The tap behind the timer has to be turned on fully, and it's easy to have someone turn it off at the tap without realising the timer needs it left on. Then go through the clock, the start time, the run time and how often it's set to water, and check that it isn't sitting on a manual off or a rain delay setting.

Check the filter

Most timers have a small filter screen or washer where they screw onto the tap, and grit from the pipes can block it so only a trickle gets through. Unscrew the timer and rinse the filter under the tap. While it's off, make sure the washer is sitting flat so it seals when it goes back on.

Check what's after the timer

If the timer opens and you can hear water going through but the garden is still dry, the problem is further down the line. A kinked hose, a split in the line, a fitting that's popped off or a blocked dripper will all do it, so walk the line while it's running and look for wet spots where there shouldn't be any and dry spots where there should be water.

When to replace it

If it's had fresh batteries and a clean filter and it still won't open, or the case has cracked and water's got inside, it's usually time for a new one, because they're not really built to be repaired. Keeping a timer out of the full afternoon sun helps the plastic last longer.

Shop related products

Pope Simple Set Single Tap Timer. A single outlet tap timer for one hose or drip line.
Pope 12mm Brass Tap Adaptor 20BSP. For a solid fitting on the tap side.
Pope 12mm C/Grip 3 Piece Set. Hose fittings for reconnecting a line that's popped off.
Pope Drip Eze 2LH 13mm x 30m. Dripline for running off a timer.

Did you know we also stock digital tap timers with up to 4 outlets and a Bluetooth tap timer you set from your phone in the shop, and they aren't on the website, so give us a ring on (08) 8536 4333 to check what's on the shelf.

The rest of the watering range is in our Pope collection and our garden centre, and if you bring the timer in we'll go through it with you.

More on watering

I'm a firm believer that the batteries in a tap timer should be changed on the same day every year, because the day they go flat is always the hottest one.

Candeece