Enjoy your infused lavender drink with ice cubes cold.
Notes
You can use dried or fresh flowers, however, I personally prefer to use dried lavender flowers because the essential oils in the flowers are easier to extract when the flowers are dried
If you use fresh lavender flowers, you will need to leave the flowers to infuse in boiling hot water until the water is completely cooled. Fresh lavender won't infuse well in cold water.
You can use hot water too with dried lavender to speed up the infusion process.
The quality of your infused lavender water will depend too on the variety, state and age of the flower buds.
You can use a normal glass, pitcher or bottle or get a special bottle or pitcher infuser (more in the post under equiment)
Use about 2-3 Tablespoons dried lavender buds per quart/liter. Use about double the quantity of fresh buds for the same liquid quantity.