Disconnecting and reconnecting the faucet and drain piping? Needs a permit. I see Frankenstein-like plumbing under sinks every week. Mostly, your renovations seem like things I would not get permitted. Not my advice really - just my opinion.
Short list of things requiring a permit in California: new dual pane windows, furnace replacement, water heater replacement, re-roof, ceiling fan, cooling unit replacement, new electrical panel, kitchen remodel, bathroom remodel, patio cover, framing alterations.
Permits trigger the installation of smoke and carbon monoxide alarms. HVAC replacement (full or partial) triggers duct testing and sealing/repairs. Pre 1978 homes need a lead certification and remediation when you manipulate and sand walls or floors.
New work on old homes require new (today's) code compliance.... more
If it wasn't built properly I don't understand how it could have passed a permit inspection. Was a FINAL permit inspection signed off by the city ? You really need to have your Realtor recommend how you should proceed. Your Realtor who represented you with the initial offer to purchase should be helping you to resolve this issue as it appears a bit complex and you will need to do some extensive research.... more