Image copyright Tom Martin/Wales News Service

A "cry of pain" to help "one of the country's poorest areas" with its £180m bill estimate to recover from flooding has been issued to the UK government.

It has been warned school budgets could be affected if Wales has to foot the bill to repair the south Wales valleys after Storm Dennis' "devastation".

Local MP Chris Bryant said Wales paying alone may "wipe out Welsh Government's capital budget" just in the Rhondda.

The UK government said it had been communicating with Welsh ministers.

There are currently 15 flood warnings and 36 alerts in place across Wales.

The Environment Agency said 40-50mm of rain had fallen over the Welsh mountains, and it was expected to cause problems further down the River Severn.

The centre of Rhondda Cynon Taff's county town Pontypridd was left under water after the River Taff burst its banks last Sunday and thousands were affected around the county by widespread flooding.

Key roads and rail lines remain shut, and former valleys coal tip sites are being watched for potential landslide threats.

Footage of a landslip on a steep slag heap at Tylorstown has worried Rhondda Cynon Taf council chiefs so much that they are physically monitoring former coal sites in the county 24 hours a day.

Media playback is unsupported on your device

The Welsh Government has pledged £10m to help towns like Pontypridd and Monmouth which were badly hit after nearby rivers burst their banks after their water hit record levels.

Now Welsh politicians have called on the new chancellor for a one-off grant of £30m to help pay for repair and restoration work across Rhondda Cynon Taff.

In a letter to Rishi Sunak, they also want council tax and business rates suspended for a year in affected properties.

Council chiefs estimate £30m of infrastructure damage in Rhondda Cynon Taff alone - with the bill for private properties across the county "likely to run to nearly £150m pounds," according to RCT council leader Andrew Morgan.

The Welsh Government funds flood defences, flood clear-ups and funding to local authorities but tax relief is a UK government call.

"Wales took the brunt of the force of this storm and we would be wiping out all of our financial resources in one of the poorest areas of the country," Mr Bryant, the Rhondda MP, told BBC Radio Wales.

"In the normal course of things this would be funded by the Welsh Government. But you would be wiping out the entire capital allocation just by dealing with the problems in Rhondda Cynon Taff. That would mean no other work on things like schools for example.

"They have announced lots of extra money in England but there isn't a single consequential penny for Wales, which is the hardest hit part of the UK.

"The whole point of the 'United Kingdom' is that if one part of the UK suffers then the whole of the United Kingdom should step in to help."

Mr Bryant added he thinks Westminster "is open to the idea" for extra funding but wants the UK government to "step up".

Analysis by Felicity Evans, BBC Wales political editor

If you've been flooded, you want help. You don't really care where it comes from. Being flooded is traumatic and it takes time and money to recover.

In these Labour heartlands, if people feel they've been abandoned there could be a backlash in the assembly elections next May.

The politicians who wrote the letter to the chancellor want extra money from the UK government.

But a lot of what they're asking for is legally the responsibility of the Welsh Government.

The UK government has promised extra money to flooded local authorities in England because they are responsible for funding councils there.

In Wales, local councils are funded by the Welsh Government which has promised ten million pounds for immediate relief, with more to come.

Reserves exist for emergencies, should the Welsh Government use theirs to shoulder the full cost?

Or is this an extraordinary situation, where the UK Government should step in? In politics, the answer to the question "Who pays?" is never straightforward.

About 550 homes were flooded across the county and Rhondda council bosses say they "currently have 50 families in temporary accommodation".

"The amount of damage is just something we haven't seen on this scale before," Mr Morgan told BBC Radio Wales.

"A lot of families don't have insurance and some businesses are being told by their insurance companies they aren't covered.

"Unless we have additional support families will be out of their homes for sometime, businesses could fold and people could lose their jobs."

Crowdfunding pages have already raised thousands for the flood-hit communities and a Valley Aid fundraising concert has been announced for next month, where Manic Street Preachers frontman James Dean Bradfield and Grammy award winner Amy Wadge will headline.

Film star Michael Sheen and Pontypridd MP Alex Davies-Jones have between them raised more than £80,000 in online campaigns.

A UK government spokesperson said: "Whilst flood defences and the response to flooding in Wales are devolved, we will continue to engage with and support the Welsh Government on flood relief and coal tip safety."

What's happening in other parts of Wales?

A full Powys council meeting on Friday will reveal what the cost of the recent storms has been to the county and what can be done to help those affected.

Councillor John Morris, who represents Crickhowell - one of the hardest hit areas of the county - said: "In my area alone over 30 residential properties were affected and about the same number of businesses.

"This includes the Elvicta Trading Estate on the outskirts of Crickhowell with its 20 or so businesses and is a major employer in the area."

Caereinion High School near Welshpool, Powys, closed on Monday because flooded roads are preventing some teachers and pupils from getting in.

Meanwhile, running water to a town marooned by flooding has been restored after almost a week without supply on Monday.

Tankers and bottled water had supplied residents in Monmouth after the town's Mayhill treatment works was shut after becoming submerged after the Rivers Monnow and Wye burst their banks.