Sounds like you want to do work that is exempt from permit. Keep in mind that if you buy a house to flip it, you cannot get an owner-builder permit. If you get an owner-builder permit, you'll be signing a clause that says you won't sell it within one year of completion of the permit. Unless, of course, you have a contractor's license.
2022 California Residential Code
SECTION R105
PERMITS
R105.1 Required. Any owner or owner's authorized agent
who intends to construct, enlarge, alter, repair, move, demolish
or change the occupancy of a building or structure, or to
erect, install, enlarge, alter, repair, remove, convert or replace
any electrical, gas, mechanical or plumbing system, the
installation of which is regulated by this code, or to cause any
such work to be performed, shall first make application to the
building official and obtain the required permit.
R105.2 Work exempt from permit. Exemption from permit
requirements of this code shall not be deemed to grant authorization
for any work to be done in any manner in violation of
the provisions of this code or any other laws or ordinances of
this jurisdiction. Permits shall not be required for the
following:
Building:
1. Other than storm shelters, one-story detached accessory
structures, provided that the floor area does not
exceed 120 square feet (11.15 m2). It is permissible 11
that these structures still be regulated by Section
710A, despite exemption from permit.
2. Fences not over 7 feet (2134 mm) high.
3. Retaining walls that are not over 4 feet (1219 mm)
in height measured from the bottom of the footing to
the top of the wall, unless supporting a surcharge.
4. Water tanks supported directly upon grade if the
capacity does not exceed 5,000 gallons (18 927 L)
and the ratio of height to diameter or width does not
exceed 2 to 1.
5. Sidewalks and driveways.
6. Painting, papering, tiling, carpeting, cabinets,
counter tops and similar finish work.
7. Prefabricated swimming pools that are less than 24
inches (610 mm) deep.
8. Swings and other playground equipment.
9. Window awnings supported by an exterior wall that
do not project more than 54 inches (1372 mm) from
the exterior wall and do not require additional support.
10. Decks not exceeding 200 square feet (18.58 m2) in
area, that are not more than 30 inches (762 mm)
above grade at any point, are not attached to a dwelling
and do not serve the exit door required by Section
R311.4.
Electrical:
1. Listed cord-and-plug connected temporary decorative
lighting.
2. Reinstallation of attachment plug receptacles but not
the outlets therefor.
3. Replacement of branch circuit overcurrent devices
of the required capacity in the same location.
4. Electrical wiring, devices, appliances, apparatus or
equipment operating at less than 25 volts and not
capable of supplying more than 50 watts of energy.
5. Minor repair work, including the replacement of
lamps or the connection of approved portable electrical
equipment to approved permanently installed
receptacles.
Gas:
1. Portable heating, cooking or clothes drying appliances.
2. Replacement of any minor part that does not alter
approval of equipment or make such equipment
unsafe.
3. Portable-fuel-cell appliances that are not connected
to a fixed piping system and are not interconnected
to a power grid.
Mechanical:
1. Portable heating appliances.
2. Portable ventilation appliances.
3. Portable cooling units.
4. Steam, hot- or chilled-water piping within any heating
or cooling equipment regulated by this code.
5. Replacement of any minor part that does not alter
approval of equipment or make such equipment
unsafe.
6. Portable evaporative coolers.
7. Self-contained refrigeration systems containing 10
pounds (4.54 kg) or less of refrigerant or that are
actuated by motors of 1 horsepower (746 W) or less.
8. Portable-fuel-cell appliances that are not connected
to a fixed piping system and are not interconnected
to a power grid.
Plumbing:
1. The stopping of leaks in drains, water, soil, waste or
vent pipe; provided, however, that if any concealed
trap, drainpipe, water, soil, waste or vent pipe
becomes defective and it becomes necessary to
remove and replace the same with new material,
such work shall be considered as new work and a
permit shall be obtained and inspection made as provided
in this code.
2. The clearing of stoppages or the repairing of leaks in
pipes, valves or fixtures, and the removal and reinstallation
of water closets, provided such repairs do
not involve or require the replacement or rearrangement
of valves, pipes or fixtures.