Philadelphia's long-troubled child welfare system is taking on water.

Even as it struggles to improve its oversight of the city's most vulnerable children, its mission has been made more difficult by a swelling caseload.

In just the last three years, Philadelphia's Department of Human Services has seen the number of children in its foster-care system grow from 4,100 to 6,100.

The impact was evident in a state audit released this month that listed 71 violations by the department, the majority stemming from the strains on the system.

The growth has left workers struggling to keep up with hotline calls and manage the responsibilities that come with children in foster homes.

"We are very clear that the numbers are stark," said Eva Gladstein, the city's deputy managing director for children and families. "We're getting more calls to the hotline, we're doing more investigations, and it creates stresses and strains on the system."

The city is second only to Phoenix in removing children from their homes, according to a report by the National Coalition for Child Protection Reform, a Virginia-based organization.

Philadelphia's removal rate is double that of New York and quadruple Chicago's. The result is an overburdened system with workers juggling huge caseloads.

Much of this is detailed in the audit the state issued, revoking the agency's certificate of compliance and issuing a provisional license to operate. A city can receive no more than three provisional licenses before the state can take over.

City and state officials have said there is an easy explanation for the growth in the system: Child-abuse reporting laws changed after the Jerry Sandusky/Penn State scandal. That has led to a spike in the number of calls and investigations while the city simultaneously aims to transition to a new system of private providers.

Hotline calls are up 30 percent compared with 2015, and investigations are up 12 percent.

Calls are also increasing statewide. The state auditor general found last week that the state's child-abuse reporting hotline dropped 22 percent of calls this year (state law requires Philadelphia County to also operate a 24-hour hotline).

But other counties have experienced more calls without an increase in the number of children placed in foster care.

In Pittsburgh's Allegheny County, the number of hotline calls increased by 28 percent, but substantiated reports went down 20 percent, and the number of children in the system decreased.

The key is how calls are handled, said Kathleen Creamer, managing attorney at Community Legal Services.

Children are supposed to go into foster care if their safety is threatened and there is no feasible alternative, but given Philadelphia's extreme poverty, the lines can get blurred.

"We're confusing safety and poverty and conflating those two things and putting children in foster care where the issue is not child safety," Creamer said.

Nearly 10 percent of all out-of-home placements in Philadelphia involved "inadequate housing," according to the audit.

Drug abuse is the most cited reason a child is taken from a home, followed by a child's behavioral problems, neglect, and physical or sexual abuse.

After the starvation death of Danieal Kelly in 2006 while under DHS care, the agency moved to outsource case management to private community umbrella agencies (CUAs). DHS still handles oversight, investigations, and the abuse hotline.

While the agency planned on shedding some of its staff, it has had to keep employees on to handle hotline calls.

Richard Wexler, director of the National Coalition for Child Protection Reform, said Philadelphia always had a high rate of removal, even before the reporting laws changed.

He said Kelly's death, coupled with the Sandusky case, had created a culture of overcaution.

"Every caseworker is thinking, 'I'm not going to have the next Danieal Kelly on my caseload,' and that's what's happening at every step from hotline, to investigator, as they keep passing these cases on to the CUAs," Wexler said.

Gladstein said she had seen no evidence the DHS staff was accepting too many children into care.

"We don't know that at all. I think it's more likely there are trends throughout child welfare after certain kinds of incidents - post-Sandusky has had an impact," she said.

The city is looking for a consultant to evaluate the ongoing reforms and work with Casey Family Programs, a Washington-based organization that assists child welfare providers, to analyze the intake process.

Decreasing the number of children in DHS care also means looking at how efficiently children are returned to their parents or placed in adoptive homes.

The audit, which looked at 2015, found that the number of children leaving care has decreased, contributing to the size of the system. More recent numbers from the last four months show an uptick in adoptions and reunifications.

Michael Vogel, CEO of Turning Points for Children, one of the 10 CUAs in the city, said 392 case managers were doing the work previously handled by 660 before the overhaul. Each handles about 13 cases, many involving multiple children. The goal had been 10 cases per worker.

"This heavy workload for the case managers, the core of any child welfare system, leaves little time for the complex work of developing and implementing a plan to move a child into a permanent living arrangement," Vogel said.

Turnover is also extremely high among CUA workers, which can slow resolution of a child's case.

CUAs have asked the city for more money to increase staffing levels. Gladstein said the city was looking to increase the CUA budget in 2017 but was still negotiating with the state for more funding.

The state's contribution was significantly lower in the 2015-16 fiscal year than in previous years, Gladstein said, despite more children entering the system.

The state did not respond to requests for comment on whether it would increase its contribution.

State DHS Secretary Ted Dallas said May 23 in an interview that the problem was not a lack of resources but a misallocation of money. He said the city should dedicate more of its budget to the CUAs.

"The initial idea was there would be a transfer of cases from DHS to the CUAs, and DHS would shift to more of an oversight role," Dallas said. "As cases got transferred, the allocation of resources has not followed. If the city is going to continue with CUAs, it needs to take a look at that."

215-854-5506 @juliaterruso