Water bowsers were deployed earlier in the week in Carmarthenshire About 400 homes are still without water in Powys as engineers work around the clock to restore supplies.
At one point, 2,000 properties in Llandrindod Wells (LD1) were without water earlier this week, and thousands more across Wales.
In Horeb, Carmarthenshire, about 50 properties are still without supply.
Welsh Water said it has been dealing with an “unprecedented” number of burst pipes due to freezing conditions.
It said it is making “good progress” with repairs, and admits there are more isolated problems elsewhere.
In Powys, operations director Peter Perry said engineers are “expending every effort today to get these customers back on supply”
In Horeb, Carmarthenshire, “air locking” in the mains is affecting about 50 homes since repairs were made at a pumping station in the county which had been causing low pressure or loss of supply to 3,000 homes around St Clears.
Mr Perry said there were still isolated problems in rural areas across Wales.
“We are also very much aware that there are isolated incidents of supply loss affecting single or small numbers of customers across the region.
“We are doing all we can to follow these up and we are looking to contact customers today to resolve these issues. I would urge customers in these circumstances not to hesitate to contact us again if necessary.”
In Llandrindod Wells, Dwr Cymru has made available bottled water at Hundred House common – near the recycling centre – and Glascwm village centre.
Homes in Cregrina, Frankbridge, Glascwm and Hundred House are suffering from low pressure caused by mains leaks.
In addition, engineers are tankering water into a local reservoir which is designed to improve pressure to help supplies return to normal.
As communities continue to be affected in Rhayader, bottled water is also being available from Sun Inn, St Harmon, and Mid Wales Inn, Pant-Y-Dwr.
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