Construction equipment is parked outside the CHA Somerville Campus urgent care clinic Friday. (Photo: Marc Levy)

Cambridge Health Alliance is beginning to reopen offices at the former Somerville Hospital after a water main break closed the building Sept. 28. The health care system will open its urgent care center Sunday and its gastrointestinal clinic Monday, CHA said in an email to patients this week.

The urgent care center’s new hours are reduced to 10 a.m. to 5 p.m. weekends and holidays and to 9 a.m. to 8 p.m. weekdays. Previously the service was open from 9 a.m. to 9 p.m. daily. The Alliance reduced hours because most demand occurred during morning and midday hours, it said.

CHA said its eye care center and laboratory will reopen “later this month.” It gave no indication when other offices, including a primary care center, inpatient psychiatric unit for teens, medical and surgical specialties and obstetrical/gynecological services would reopen.

Repairs are apparently concentrated in the lower level of the building, with an entrance on Highland Avenue. CHA asked patients not to use that entrance and access the building from Tower Street, which opens onto upper floors.