One tap, one or several zones — and a battery that must not die

The best water timers for 2026

A water timer is a valve with a clock, screwed to an outdoor tap, and the shelf divides on a single number: the channels. A single-channel unit waters one thing on one schedule. A two-channel unit runs a lawn sprinkler in the evening and a drip line for pots in the morning, from the same tap, on separate programmes — and that is the difference most buyers discover they needed after the first summer. Four-channel units appear here too, aimed at people who have split a garden into zones. Everything else follows from the connection: these thread onto a standard outdoor tap, and the thread size — quoted in inches, with an adapter usually in the box — is the compatibility question that decides whether the thing can be fitted at all. The programmes are where the shelf actually differs. The simplest units repeat one interval; the mid-range ones hold weekday schedules; the Wi-Fi models on this shelf, which are the newer half of the corpus, move the schedule into a phone and add remote start. Whether that is worth anything depends entirely on the power: almost every unit here runs on alkaline cells, and a flat battery on a timer fails closed on some models and open on others, which is a difference the listing rarely states and the water bill eventually does. Two more columns matter. A rain sensor input is what stops the garden being watered during a downpour, and it is either present or absent — no firmware substitutes for it. And the display, because a programme you cannot read at dusk in the rain is a programme you will set once and never adjust. We compare channels, connection, programmes, power, rain sensor and display.