Severn Trent Water has warned of the possibility of flooding and the Met Office has issued a yellow warning for heavy rain on Sunday, following an expected wet Saturday.
The weather experts say between 40-60 mm (1.5 to 2.3 inches) of rain can be expected during the weekend with some spots perhaps seeing 100mm (3.9 inches) or more.
Much of Powys is included in the warning, which comes close to Newtown and covers Llandrindod Wells.
The Met Office says heavy rain could lead to some disruption to bus and train services, spray on the roads, and a "likely" prospect of flooding of a few homes and businesses.
However no flood alerts were in force in the region with Natural Resources Wales or the Environment Agency on Saturday morning.
Severn Trent Water 's website warns that, as the weather system works its way across the country, there is a possibility of flooding of rivers and streams, on highways and around homes.
They advise people affected by flooding from river or streams to contact the Environment Agency and they will be able to assist further.
You can find more information and contact details on their website or their Floodline number on 0345 988 188.