Beds, Bucks and Herts braced for more flooding
Heavy rain expected in Bedfordshire, Buckinghamshire and Hertfordshire from 19:00 GMT will last for several hours, the Met Office warns.
Heavy downpours lashed the counties overnight, swelling rivers and canals.
Buckinghamshire Fire Service received nearly 80 calls for help as water collected on roads near Aylesbury, Haddenham, Great Missenden and Chesham.
Calls were also received from other large towns and outlying villages, a fire service spokesman said.
The Environment Agency issued flood warnings for Watford, the River Colne at London Colney and Colney Heath, the River Lee at Hertford and Ware in Hertfordshire.
An emergency rest centre has opened at Stoke Mandeville Stadium for residents of flooded homes in Ellen Road in Aylesbury.
Flood warnings also covered the River Great Ouse at Buckingham and Newport Pagnell and in Bedfordshire at Clipstone Brook and the River Ouzel at Leighton Buzzard.
The M25 clockwise had three of the four lanes closed between J16 and J17. Link roads from the M40 J1A (both southbound and northbound) to the M25 J16 clockwise were also shut.
Drivers were experiencing major delays on the M25 in Buckinghamshire near the M40 junction due to flooding.
The Highways Agency was working with Buckinghamshire County Council to try and reopen the lanes as soon as possible.
Little Wymondley village between Hitchin and Stevenage in Hertfordshire was completely flooded and the police were preventing vehicles from entering or leaving.
The A421 is flooded at Marston Morteyne between Bedford and Milton Keynes.