It really depends on environment, and how much bacteria is in the sample when you collect your water.
when I need it to culture faster I can use pond water or any water really that doesn’t have chlorine or chloramine and mix in already cultured bacteria, and the process will speed up tremendously depending on how much you mixed in.
when its warmer like 2weeks - a month depending on light and heat. Cooler it has taken me as long as 3 months. Ive found it cultures the fastest under 5000k around 75-80 light with a heating pad under it. Due to fall comming my next batch I started yesterday I put in my tent but during mid summer I put outside.