There has been a remarkable recovery in the countryside around Lithgow after 10 days of rain.

The wet spell over much of NSW, triggered by remnants of a tropical cyclone, began back on January 28 and there has been rain to varying degrees every day since then.

Since the rain began Lithgow has had an official reading of just over 126 mm which translates into five inches on the old scale.

Unlike neighbouring centres the rain over the local area has generally provided a good soaking, returning sub soil moisture without damaging downpours.

It has been a different story in the Blue Mountains where some locations have had their heaviest rain in years and where flash flooding and mud slides have caused damage and disruption.

The torrential downpours around Katoomba and the Lower Mountains in particular have brought considerable benefit to the catchment for the Sydney water supply.

By yesterday the run off had added five per cent to the storage in Warragamba Dam.

In real terms this is a massive amount of water and represents three months supply.

The water level had already risen 1.7 metres, the biggest input at Warragamba since 2007.

Water flowing down Farmers Creek and the Coxs River has also meant a slight rise in levels in Lake Lyell.

At the severely drought stricken Oberon Dam there was a rainfall registration of 66 mm but this only served to enable water levels to remain unchanged for the week.

Yesterday the storage was a perilous 9.8 per cent full.

Downsides to the rain have been the emergence of large numbers of potholes on district roads and the cancellation of outdoor sporting fixtures.

But as far as home gardeners and the local rural industry is concerned there is no downside — the rain was just what was needed to help rectify the impact of the scorching temperatures experienced in mid January.

Yesterday the Weather Bureau was predicting the possibility of more rain and thunderstorms right through until Sunday, with the one exception of Friday when sunshine is tipped at last.