HARRISBURG — Legislative leaders on the five-person group redrawing state lawmakers’ district lines based on census data heard Tuesday how the delay in the release of updated population figures may require them to move more quickly than anticipated.

Comprehensive census numbers might not reach the state’s Legislative Reapportionment Commission before the end of September, and counties need the new maps by Jan. 24 in order to provide the requisite information to candidates and others circulating nominating petitions during a period that kicks off on Feb. 15.

The chairman, former University of Pittsburgh chancellor Mark Nordenberg, said census data, which had once been expected by April 2021, will arrive in less user-friendly form in late August, then “in quote, ‘final form’ at the end of September, and even then there are adjustments to the data that will need to be made.”

“The key clash, if I can call it that, is the intersection — or lack of intersection — between the reapportionment process and the deadlines for primary elections,” he said.

After the commission produces the new maps for the state House and Senate, and after any appeals have been decided by the state Supreme Court, then county boards of election need about three weeks to prepare for the petition gathering process to begin in February.

Candidates have until March 8 to submit signed nominating petitions to appear on the May 17 primary ballot.

Allegheny County Sen. Jay Costa, the Democratic floor leader, said one solution may be to compress the 13-week period between Feb. 15 and May 17.

As for a potential delay in the May 17 primary date, which would require passage of a new law, a House Republican spokesperson said earlier Tuesday that the GOP caucus does not currently support that idea.

Pennsylvania lost a congressional seat because of the census, dropping its delegation from 18 to 17 members. The 50 Senate and 203 House districts must be compact and contiguous, and as equal in population to each other as “practicable,” with no districts dividing counties, cities or towns unless absolutely necessary.