Other writers reflect my experience; hiring at WSSC is exceptionally slow, think MONTHS not days. And lots of silence. If you are interested in a job soon, skip WSSC.
Further, my sense is that WSSC may have been threatened with legal action at some point regarding their hiring as the process is EXCEPTIONALLY methodical, documented, observed, and detailed.
I was interviewed by four technical specialists with an HR observer in the room. They had a list of 15 technical questions in my engineering field, and wouldn't give any context beyond repeating the question. Each of the panelists wrote down impressions regarding my answers to every question. It wasn't a conversation, it was more like a test. Followed with five 'personality' questions, like "tell me about a time when you faced a tough challenge, etc." nothing out of bounds.