Restrictions on new shared houses across Brighton and Hove will come into force in the summer.
A proposal to tighten the rules won unanimous support from a council committee which voted to bring in a citywide “article four direction”.
The move will cover houses rented by three people or more who are not related but share facilities such as a bathroom and kitchen.
An “article four direction” currently covers five electoral wards in Brighton where student demand has led to a big rise in the number of houses in multiple occupation (HMOs).
Once the citywide rule change takes effect, planning permission would be required to turn a family home into a shared house.
Permission will only be granted if fewer than 10 per cent of homes within a 50-metre radius are already HMOs.
Conservative councillor Dee Simson said that something should have been done sooner as the increasing number of shared houses was “changing the nature of the city”.
She shared her own experience of living opposite a house shared by young professionals in Woodingdean.
Councillor Simson told the council’s Tourism, Equalities, Communities and Culture Committee: “A bungalow opposite me that my grandfather built, that was a two-bedroomed tiny little bungalow … two bedrooms, kitchen, bathroom and front room … now it’s a seven-bedroom house. It takes up the whole site.
“Next door there’s another one. This is not student accommodation. It’s professionals. I know they need accommodation but those two properties have changed the nature of the road.
“This was planned as a small family cul-de-sac. The person who owns that house opposite is getting £4,000 a month in rent as opposed to £1,000 from a family.”
She told the committee on Thursday (16 January) that she understood the problems in Moulsecoomb and Bevendean with student housing and hoped that the citywide rule change would prevent a creep across the city.
Green councillor Steph Powell said that there had been great challenges with increasing numbers of shared houses in the city.
She said: “This will make an impact in Hanover and Elm Grove. The sadness of it all is we can’t do anything about the HMOs approved before this.”
Labour councillor Nick Childs said that the move was a “significant step forward” to regulating shared houses to prevent the deterioration of areas.
He said: “The situation with HMOs in my view is a symptom of a broken housing market.”
Since 1979, he said, “there has been a virtual stagnation of social house building, a scrapping of proper rent and tenancy regulation and incentives given to people to invest in property.”
He said that landlords were able to extract the maximum amount of profit without offering social value.
The rule change was approved by the council’s Tourism, Equalities, Communities and Culture Committee at Hove Town Hall on Thursday (16 January).