A "typical unruly family" costs taxpayers almost £275,000 a year, a council said today.
Westminster Council said the costs included those incurred by police, the NHS and the council, as well as the burden of welfare benefits and the cost of associated problems like drug abuse and truancy.
The annual figure, some £273,781, includes a year's foster care at £900 per week, £24,000 to tackle the risk of a young prolific offender and £23,200 to deal with domestic violence in each nuisance family, the council said.
Other costs included £13,000 for an eviction, almost £20,000 for six months' temporary accommodation post-eviction, and more than £17,000 to tackle substance misuse.
Dealing with a career criminal cost more than £8,500, while graffiti cost almost £6,500 and issuing an Anti-Social Behaviour Order (Asbo) cost more than £5,000.
But the council said its "tough love" Family Recovery Programme saved £2 million over the last year following falls in anti-social behaviour, domestic violence, poor parenting and truancy.
The scheme, which costs about £19,500 per family, involves them signing a contract setting out their responsibilities and the potential consequences of persistently refusing support, which could include care proceedings, eviction, Asbos and, in the case of criminal acts, prosecution.
In return, families get "targeted and intensive intervention" from the council, police, the NHS and the voluntary sector to provide them with support to get their lives back on track.
Early indications show the scheme saves more than £40,000 in the year the family is engaged, the council said.
Children's Minister Tim Loughton said: "The projects provide immediate and longer-term reductions in service costs. In the current economic climate, it is only when agencies work together and pool resources that we can achieve vast improvements to services without vast investments."
A study of 50 families found the scheme led to an 83% cut in the average number of "suspected offences" per month, a 69% cut in "accused offences" and a 48% fall in reported incidents of anti-social behaviour.
Daniel Astaire, the council's cabinet member for families, said: "At a time of unprecedented pressure on budgets, the era of throwing money at difficult social problems is most definitely over and local authorities urgently need to fundamentally rethink the way they tackle family breakdown."