Welsh Water advice for customers follows dry April
Welsh Water says it is "carefully monitoring and managing" its water resources, following the driest April in Wales since 2007.
The company said restrictions were not "envisaged" but it wanted customers to play their part by using water "wisely".
"We are asking our customers for help so we can maintain your water supplies," it said.
However, reservoir levels were said to be "holding up well".
Welsh Water, which provides water and sanitation services to 1.2m households, said it had spent an extra £5m following the dry spell last year to improve its ability to transfer water to where it was most needed.
"Our reservoir levels are holding up well across the region and are on average 91% full, which is what we would expect for this time of year," it said.
"The warm dry weather is forecast to continue and although we haven't had a hosepipe ban for 21 years, we want to keep it that way.
"We are doing a lot of work to manage resources to make sure supplies remain healthy for the summer months."
Changes in lifestyles in recent years have also been blamed previously for putting increasing pressure on water supplies.
Culprits include garden sprinklers and large children's paddling pools that are increasingly common in back gardens.
BBC Wales meteorologist Derek Brockway said it had been the driest and sunniest April in Wales since 2007 and the warmest on record.
However, he said the recent fine spell was set to end over the next few days with low pressure causing unsettled weather and some rain and showers.