LP12UH runs to 20metres (the type of LeakyPipe you will find in Vegetable Watering Kits)

LP12H runs to 50metres (and is the most popular pipe for general landscape watering use).

LP12L runs up to 100metres (the type of LeakyPipe in the Hedge Watering Kits)

These are recommended maximum lengths for single laterals of LeakyPipe, from where the water is introduced, (plugged at opposite end). This isn't a limit on the amount of LeakyPipe that forms a system, as several laterals can be used at once.

To help put a perspective on this, a typical domestic water supply is capable of running a cumulative total of about 300metres of LP12H at one time. (In any combination of lengths of up to 50m each).

If you want to water more than 300m in your garden, design your layout into 'zones' with different zones being watered at different times. A dual output tap timer can help with this.