Already under criticism for plans to end the 2020 census at the end of September, a month earlier than previously scheduled, the U.S. Census Bureau expects to finish up its most labor-intensive operation for getting an accurate head count even earlier in one of the largest U.S. cities.

Door-knocking operations for the 2020 census are expected to end in the San Diego area on Sept. 18 instead of the end of the month, for census takers, also known as enumerators, who visit homes that haven’t yet responded to the questionnaire, according to a Census Bureau official.

“We hope all of our workload will be complete and there will not be any more enumerators out on the street,” Roberto Garcia, a partnership specialist in San Diego, said almost two weeks ago during an online meeting with metro San Diego leaders who are helping motivate residents to answer the census questionnaire.

Garcia said people who haven’t yet responded to the census questionnaire after the door-knocking stops will still be able to do so online, by mail or by telephone.

Census Bureau spokesman Michael Cook said that there are some places in the U.S. that will finish with the door-knocking phase earlier than the Sept. 30 deadline because they have completed the needed work.

Cook didn’t say which other areas may wrap up before the end-of-September deadline.

Between the time these areas finish with door-knocking and the Sept. 30 deadline for ending the head count, “they are going to take a fine tooth comb and make sure nothing is missed,” Cook said.

A coalition of cities, states and civil rights groups are suing the Census Bureau to stop the statistical agency from ending the head count at the end of September. The 2020 census will be used to determine how $1.5 trillion in federal spending is distributed and how many congressional seats each states gets in a process known as apportionment.

Because of the pandemic, the Census Bureau revised its deadlines so that the 2020 census would finish at the end of October. But the bureau shortened that deadline to the end of September last month. That came after it became clear the Republican-controlled Senate wouldn’t take up legislation passed by the Democratic-controlled House that would extend the Census Bureau’s deadlines for turning over apportionment and redistricting data.

The Senate inaction coincided with President Donald Trump directing the agency to exclude people in the country illegally from figures used for redrawing congressional districts, according to a lawsuit filed in San Jose seeking to stop the count from ending in September.

More than a half-dozen other lawsuits are challenging Trump’s order, which civil rights groups say is unconstitutional and an attempt to limit the power of Latinos and immigrants of color.

A third of San Diego County’s 3.3 million residents are Hispanic, according to Census Bureau figures.

Households that require door knockers to gather census answers typically are among the hardest to count in a census.

“Any additional truncation of Census household data collection, especially if concentrated in particular geographies, is beyond irresponsible,” said Thomas Saenz, president and general counsel of the Mexican American Legal Defense and Educational Fund. “Any whiff of possible political targeting — suspicions obviously triggered by the Trump administration’s troubling pattern in other areas — severely undermines confidence in Census 2020.”

Saenz’s organization and other civil rights groups on Tuesday asked a federal judge in Maryland for a temporary restraining order that would stop the Census Bureau from ending the count early and let it continue through the end of October. The request also asked that the deadline for turning in apportionment data be pushed back from the end of the year to the end of next April.

The request says Hispanics, Asian Americans, Blacks and immigrants are at risk of being undercounted if the census ends early.

The door knockers “are essential for counting households that do not self-respond to the census questionnaire, a greater proportion of which tend to be minority households,” said the motion for the temporary restraining order.