+1. We know someone who had a lot of work done by unlicensed contractors without permits. When it came time to sell, they had to spend a lot to get it right. In my experience licensed contractors will get permits, because they don’t want to put their licenses at risk to save you money. In Fremont, up north from SJ, it hasn’t been a big problem.
Sometimes it will seem to be a pain. When we had new windows put in we had to make the one in my wife’s office bigger, so she could get out of it in case of a fire. A pain, but if there ever is a fire it might come in handy.
I have no idea if the renovations in the OP need a permit, but it doesn’t hurt to ask.
The work, as described, requires a permit because of the plumbing work and the fact that you’re improving the value of your home (potential property reassessment). You won’t need to draw up any architectural plans since nothing structural will be done. Now, this is not to say you can’t try to do the work without a permit. You can find contractors who would be willing to do the work without a permit. Here’s the risk you take … there will be hammering and other noise going on in your house. Contractors will be going in and out of your house. Their trucks will be parked outside your house. If a neighbor reports on this (only takes a phone call!) a city inspector may show up unannounced and you’ll be cooked. Not only will you have to go get the permits, but there could be a fine. Also, as mentioned, there’s the downstream potential problem when you sell the house. I just went through a very similar remodel and opted for the permits. That’s my recommendation.
That’s the risk when you start messing with an older house - once you start doing something, you have to update to current code. We’ll probably be facing this on any number of fronts, too.
Our house is about 55 years old - the house my wife grew up in is about 130 years old. It is just a matter of how the code has changed since the last time you did a change. The new one is that CO detectors are now required, but that at least is a cheap and easy thing to fix.
This happened to my brother’s girlfriend as well. Go to your local municipality, tell them what you’re doing, and if they say you need a permit, just get it.