In California they cannot legally rake as a % of pot size the way most other locations do it, they take what is called a drop instead. Basically, they take $1 as soon as the hand is dealt (even if you chop, the SB pays the $1), plus the BBJP (typically $1-2) if you're in a jackpot game, and then as soon as there is a flop they take out the drop, which I think is generally $5-7 (I think this is total, including the $1 they may have taken out already).
So small pots are heavily raked. What this means is that you should never be just limping in a blinds battle or with 1 other limper. In a 1-3 game, if both blinds limp, there is $6 in the pot...and then they take $5 for the drop and $1 for the BBJP, and now you have $0 in the pot you're playing for. Better to just raise or fold.
Here is the best thread on taxes. It is out of date, but most of the info is probably still right:
https://forumserver.twoplustwo.com/5...-poker-740589/ . Short version: you owe taxes on any won amount, and you do not get to net your wins and losses unless you are a professional gambler and also file a Schedule C.