Households and businesses have woken up to a Christmas Eve clean-up after emergency services faced hundreds of calls for flooding help.
Downpours on Wednesday saw South Wales Fire and Rescue Service deal with 500 calls in a matter of hours.
Firefighters were called to flooding at properties in Cardiff, Newport, Monmouthshire and Vale of Glamorgan.
Huw Williams from Natural Resources Wales said rivers were still rising on Thursday morning.
Wednesday's downpours saw parts of the M4 and M48 closed and train services cancelled.
"Flooding can have a devastating impact on people's lives... We are hoping for a bit of respite over the next few days but we are expecting more rain, unfortunately, later on in the weekend.
"Our staff have been out all night... trying to protect properties but we are asking people to be vigilant."
Enzo Nigro, the senior manager of Potters Pub in Newport, said he spotted his cellar had flooded via the CCTV.
"It's [the future] not looking bright at the moment, this was the last thing we wanted before Christmas, the cherry on the cake that shows how bad this year has been," he said.
'People rushed to help'
Richard Williams said neighbours helped build a barricade in front of his house in Mathern, Monmouthshire, after water started rushing in off nearby fields.
"It was a Dunkirk spirit when the call went out, the village rallied together, people we don't even know," he said.
"Mathern does have that community spirit so we shouldn't expect anything less. I was absolutely amazed with the people who turned up to help us."
Mr Williams said emergency services had to use a boat to transport people across the village after the flood waters rose. "At the moment, everyone is thankful that the rain has stopped and it seems to have subsided slightly," he said.
Lian James has praised the community effort after her mother's house in Sully flooded.
"A cry went out for help on the Sully Community Hub and everyone turned up with dehumidifiers, buckets... everyone was amazing
"An upsetting story but with an amazing response."
A man who provides free second-hand bikes to children whose parents cannot afford them posted on Twitter to offer scooters or bicycles to anyone who lost Christmas gifts in the flooding.
If you are in Newport and have lost Christmas presents in todays flooding....let me know.— PuffaJones (@PuffaJones) December 23, 2020
I do have some smaller bikes,scooters and balance bikes ready to go if needed.
All bikes are FREE to a family in need and I am happy to help.#freebikes4kids #cycling #community #recycle pic.twitter.com/Grcw3VvbhX
Russell Thomas, general manager at Glamorganshire Golf Club, said he "feared the worst" when he turned up to work this morning.
Because the club house is lower than the golf course, water often runs off the course into the club house.
"The rain was so bad that the pumps in the cellar couldn't deal with it," he said.
The cellar was submerged in about a foot of water, but it could have been a lot worse.
"You do fear the worst when the pumps are over capacity but I have seen the cellar flood quite badly before with barrels bobbing up and down," Mr Thomas added.
Christmas Eve @glamgolf 2020 style - mopping up cellar followed by social distanced party with tonic water and out-of-date crisps #stockloss #Hospitality #penarth #flooding #golf Stay safe everyone and #HappyChristmas 🎄🎅 🎁 pic.twitter.com/sTG3CQMnZ8— Russell Thomas (@RTgolfmanager) December 24, 2020
The Newport home of Lauren Torjesen was also damaged in the floods.
"If I don't laugh I will cry," she said.
"The electric has to be turned off so I don't know what we'll do with all that good food."
In Newport city centre, shops and roads were flooded.
Mary Pring, 78, from Newport, has had to abandon her plans to shield alone over Christmas due to flood damage in her home.
"Absolutely dreadful, I'm supposed to be shielding, which I was, I was going to stay on my own on Christmas but now I will have to go to my children.
"I couldn't live in that, it's dreadful."
Mrs Pring's son Nicholas said water saturated all of his mother's carpets.
"This has been going on now for numerous years, what happens is a backfill of water fills up the street."
Arnold's Lighting and Electrical on Skinner Street, said on social media: "There are no words to describe the devastation... water is now almost over the top of the counter.
"We have lost everything. What a 2020."
Newport council's leader Jane Mudd said all its available teams were out on Wednesday evening "doing everything we can do to assist as much as possible in the worst affected areas".
When her dad's home was flooded in Sully, Vale of Glamorgan, Maris Lyons put on her wellies and went over to help.
"It was devastating and shocking, the water was so deep and as I arrived, the elderly couple who live next door to my parents were being lifted out on a man's shoulders," she said, adding a dog had swum out of a neighbouring property.
"It's a scene that I never thought I'd imagine I'd see."
A Met Office weather warning was in place until 02:00 GMT on Thursday, affecting most of Wales, apart from parts of six counties in north Wales.
Cardiff council called on residents to help clear drains of debris and leaves to reduce water levels.
A spokesman said: "The rain has filled up the brooks and streams which are now higher than the outfalls. This means the drains can't empty and are consequently backing up."