Two quotes for the "same" job can be thousands apart because they include different work. Here is what to look for in the most common Newport Beach jobs.
Water heater replacement
A full replacement includes draining and removing the old tank, the new unit, new water and gas connectors, a full-bore cold water shutoff if the old one is a gate valve, unions within 12 inches, seismic bracing, venting checks, the City permit and the inspection. If your home has a pressure regulator or a check valve, an expansion tank is often part of a code-compliant install. Ask whether haul away is included. Attic and tight closet installs take longer, and garage units on the Peninsula may need corroded gas risers replaced. See water heater repair and replacement.
Tankless conversion
Going from a tank to tankless is more than a swap. Many homes need a larger gas line, new venting through a wall or roof, a condensate drain for high-efficiency units, an electrical outlet and isolation valves for future descaling. That is why the published range for tankless installation is wider and higher than for tanks. See tankless water heaters.
Drain and sewer work
Clearing one slow sink is a short visit. A main line stoppage that keeps coming back usually calls for a camera inspection to find out why: roots, a belly, a broken joint or sand washed in by a flood. Hydro jetting costs more than cabling but scours the whole pipe wall. A camera first means you pay for the right fix, not the most expensive one. See sewer line camera and repair.
Slab leaks
Slab leak costs have two parts: finding the leak and fixing it. Electronic leak detection locates it before anyone cuts a floor. The fix can be a spot repair through the slab, a reroute of that line through the attic or walls, or a full repipe if the copper is failing in several places. Flooring repair is usually separate. See leak detection and slab leaks.
Repipes
The published range is very wide because homes are. Number of bathrooms, single or two story, PEX or copper, and how much drywall must be opened and patched all move the price. Ask whether wall patching and paint are included or left for another trade. See whole-house repiping.