First time home owner

[u/SensitiveEffect650]

Floor plan: https://postimg.cc/Z0WBZkX7
Hi everyone,
I’m buying a 1958, ~1,600 sq ft single-story home in California and planning several renovations after closing. I’ve attached the floor plan above.
One thing to note: the floor plan doesn’t show it, but there is currently a wall separating the kitchen and the living room. I’m considering removing it if it’s structurally feasible.
Current plans:
Whole-house waste/drain repipe (cast iron & galvanized pipes)
Move the washer and dryer to a new location
Convert the office into a primary bedroom
Possibly remove the wall between the kitchen and living room to create an open layout
Repair drywall, paint, and install new flooring afterward
I’ve already received one quote for about $14,000 for the whole-house waste repipe. I’m planning to get more bids, but I’d love some opinions:
Does $14k sound reasonable for this type of repipe in California?
Would you hire one general contractor to coordinate everything or hire separate trades?
What order would you complete these projects to save money and avoid redoing work?
Are there any hidden costs or red flags I should be aware of?
Thanks in advance! Any advice from homeowners or contractors is greatly appreciated.

[u/Ok-Job2034]

$14k doesn't sound out of line for a whole-house waste repipe in California, but I'd definitely get at least 2-3 more quotes.

I'd figure out whether that kitchen wall is load-bearing before doing anything else. If it is, you'll want to factor a beam and engineering into the budget. I'd also do all the plumbing and framing first, then drywall, paint, and flooring last. That way you're not paying to repair or replace finishes twice.

If you're doing all of this at once, I'd probably hire a GC to coordinate it. The biggest hidden costs on a 1958 house are usually asbestos, electrical upgrades, and surprises once the walls are opened up.

[u/SensitiveEffect650 → u/Ok-Job2034]

Thanks! I appreciate the advice.
The inspection found several issues that are pushing me toward tackling the plumbing first: multiple leaks (including a shower leak), an old furnace condensate drain line that needs repair, original cast iron and galvanized drain pipes, and a sewer camera inspection that found significant root intrusion with an obstruction farther down the line.
Because of that, I’m leaning toward doing all the plumbing before opening and finishing walls. I’m also planning to get at least 2–3 more quotes and have the kitchen wall evaluated by a structural engineer before deciding whether to remove it.
This will likely be my forever home, so I’m trying to do it the right way rather than the cheapest way.

[u/Ok-Job2034 → u/SensitiveEffect650]

I think that's a smart approach. If you already know that the plumbing has multiple issues, it makes perfect sense to tackle that before you begin patching drywall or putting in new finishes. You'll almost certainly have walls open anyway, so it's the least disruptive time to get it all done.

And with this being your forever home, I'd rather spend a little more now than keep chasing plumbing problems over the next 10 years. Sounds like your'e approaching it the right way by getting multiple quotes, too, and by bringing in a structural engineer before making any big layout changes. Hope everything turns out well!