London Colney and Radlett residents have been warned to "be prepared" for flooding after the Upper River Colne and Radlett Brook were placed on flood alert.
The government has issued the warning after heavy rain returned to Hertfordshire for the second time this week.
With flooding from the River Colne believed to be "possible", residents of London Colney are said to be most at risk, with warnings also in place for Colney Heath, Radlett and Borehamwood.
The gov.uk website says: "We are monitoring rainfall and river levels and closely monitoring the situation.
"Avoid using low lying footpaths and any bridges near local watercourses."
On Monday, St Albans and Harpenden were battered by floods, although neither the River Ver nor River Lea are on flood alert at time of writing.
The Met Office has issued a yellow weather warning across the county until 9am tomorrow.
Further information can be found at https://check-for-flooding.service.gov.uk/target-area/062WAF28UpColne.
The page will be updated by 9am tomorrow.
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