Councillors who will decide if a mental health hospital is built in Somerset have toured a similar unit.
The 75-bed hospital at Chelston would be low to medium secure and treat some patients with criminal backgrounds.
Montpelier Estates, the firm behind the £20m Wellington plan, took councillors to see a unit in Stirchley, Birmingham.
Persimmon Homes, which is building houses near the site, said it was opposed to having a "different class of development" as a neighbour.
Montpelier Estates has submitted plans for a site at the junction of the A38 and B3187 to Taunton Deane Borough Council.
Persimmon has said it would withhold part of a £443,000 community facilities payment should the hospital receive planning permission.
Simon Perks, managing director of Persimmon Homes South West, said: "We would think twice about offering the level of affordable housing and other contributions - highways and education contributions - if it was a different class of development next to our scheme."
Montpelier Estates, which hopes to create 225 jobs, has previously said it hopes to avoid some of the negative public response encountered by other mental health hospital developments elsewhere in the country.
Spokesman John Thorne said: "The purpose of the visit is to allow councillors who are involved in the planning and decision-making to actually go and see one of these hospitals at work, see it in action, see it in the setting it's in with residential development across the road from it."