Three-quarter homes give people who are homeless, leaving prison or seeking substance-abuse treatment a place to stay. But critics say the houses are unregulated and sometimes unsafe.

The unregulated rooming houses often feature crowded, unsafe conditions. But even some critics point out that they play an important role in keeping people off the street.

At some dormitories for homeless people, lawyers allege, landlords forced tenants to attend particular drug programs and failed to provide safe housing. But operators say they were trying to do…