My girlfriend lives in a 25 year old 3bd/2br rental house in far NW OKC. Her hot water line burst under the slab and flooded the place pretty bad.

She called her landlord, he came out with a plumber and they were able to locate the leak, however the condition of the pipe required a "repipe" apparently from what I understand. Basically the main hot water line runs from the gas hot water heater in the garage to a central area in the house where it splits off and goes to each destination. Apparently this "main line" is rotted for some reason and is no longer usable. The main line was capped off at this junction area. The owner told my girlfriend he is going to install a small electric hot water heater under the kitchen sink, which will heat the water for the kitchen and two bathrooms. I was kind of scratching my head after she told me this.

Well my question: Isn't this against some sort of building code? I would think so as it would not appear it would be supplying adequate hot water for the house. I guess it is an existing building so maybe this kind of "fix" is perfectly acceptable/legal. A secondary thought was the fact that the dishwasher, fridge and lighting in the kitchen are all on the same outlet/breaker as where the hot water heater is going, seems like it might be overloading that circuit or wiring.

If it's a new hot water heater, the city has to approve it and will have to inspect it.

The last time I had to have a (replacement) hot water tank installed no permits had to be pulled. However, the licensed plumber had to be sure that all of the existing air supplies, venting, drain pan, elevation of the unit and so forth was up to code (which it was). I will say this: It is unlikely that the single, point of use, electric water heater will keep up with the demand for hot water in a residence such as that described. Maybe the landlord could reduce the rent by about 50% to balance things out . . .

I'm a licensed electrician, not a plumber. But the level of work that requires a permit for plumbing or HVAC somewhat parallels electrical and vice versa. Replacing a water heater wouldn't require a permit. It's service work. Relocating a water heater probably should be permitted. Most wouldn't bother pulling a permit but technically it's a large enough change it probably should be done to be legal. I also agree with RM that an electric unit under a sink isn't going to keep up with two bathrooms and a kitchen.

It sounds like they plan on installing a whole house tankless unit under the sink. You can probably find one that fits in that space. The BTU capacity for a whole house system used to be only available in gas models, however there are now electric models that are available. These require a large electric service, something on the order of 3 separate and independent 50 amp double pole breakers with a minimum electrical service of 200 amps. My biggest concern would be with the flow of water in the house and the condition of the remaining in-slab pipes. With the relocation of the tank and the associated upgrade of the electric panel, my guess is that permits should be pulled.

Typically service work not requiring a permit is repairing and/or replacing minor parts of systems. A thermostat on a hot water tank is a minor part. An entire hot water tank (or electrical panel, air conditioning unit, furnace) is not. A new circuit for a tankless heater most definitely requires an electrical inspection in addition to a plumbing inspection. You can call your city permit department and ask. Google building permit and the city you live in and you'll find a phone number.

OKC 297-2948

City of Oklahoma City | Development Services (http://www.okc.gov/devservices/buildpermits/)

But it happens frequently that people do this kind of work and do not get permits.

I faced a similar but smaller situation years ago and elected to go with the "on-demand/instant/tankless" option. I used a contractor who is a licensed plumber and electrician, but he told me that a permit wasn't necessary. This was a very small unit that fit inside a vanity, so perhaps there is a permitting threshold defined by electrical load, BTUs, water output or other.

But I wouldn't provide the city with the property's address or owner's name. If an inspector shows up, it will be obvious who tipped off the city, and then your girlfriend will be tossed out and have to move in with you. Unless, of course, that's your ulterior motive!