People are being urged to conserve water after the hot weather combined with people staying home during lockdown resulted in "record demand."
Welsh Water said demand over the past 72 hours has been higher than what was experienced during the heatwave of summer 2018.
The not-for-profit company said it had already been experiencing increased demand for water since lockdown began, but said the recent hot weather had caused that demand to surge.
It comes as the country experiences lower than average rainfall, down 50% in April and 30% in May.
The company said it has ramped up operations, working to ensure water treatment works can keep up with demand and - in places - using water tankers to top up local water systems.
Welsh Water has also issued the following advice to customers:
Don’t leave the tap running while washing hands or brushing teeth
Take a shower instead of a bath
Wait until the washing machine and dishwasher are full before putting them on
Don’t fill the paddling pool to the top – and when you’ve finished, use the water on the plants in the garden
Don’t use a sprinkler on the lawn to keep it green – the colour will soon come back once it rains
Ian Christie, Managing Director of Water Services said: “Peaks in demand normally only last a short period but with more people at home due to the COVID-19 precautions we’re seeing a sustained period of increase in demand. The demand then over the weekend reached unprecedented levels which even exceeded what we saw at the peak of the 2018 heatwave.
“Meeting spikes in demand naturally brings with is some additional challenges for the company and people will have seen our teams out and about over the weekend working to make sure that we kept the water flowing.
"While we will do all that we can, it would help us as well if customers play their part as well by avoiding wasting water. We know that water is playing a crucial role at the moment in maintaining personal hygiene to tackle Covid-19, but there are so many simple things we can all do to save water at home.
“Garden sprinklers for example are one of the biggest consumers of water in the garden as they use on average 1,000 litres of water every hour. This is the equivalent of what a typical family would use inside the house in two days. By avoiding using sprinklers, or investing in a water butt to collect rain water, people could use significantly less water.
“Another way customers can help is by reporting any leaks to us which they may notice so that we can get a team out straight away to look at it. By working together in this way was can help ensure that we keep the water flowing through the summer”.