tying into galvanized plumbing with PVC

My house is about 80 years old and is full of galvanized plumbing that for the most part is in pretty good condition. Alot of this plumbing leads to nowhere though, which for this project is very convenient. Im looking to put a laundry sink in my basement and the hot and cold water pipes both have pipes that lead off of them and are capped at the ends. Im wanting to tie into these and us PVC to plumb my sink. They are 3/4" dia. and that caps look fairly new. Does anyone have any advice for doing this?

The external look of the cap is not what counts, rather, the internal diameter of the galv. pipe.
Is it mostly closed off by rust?

try removing the cap and see how heavy a flow you have.
But, be careful, if it's very old galv, it might just collapse and be very difficult to get back together.

Adapting galvanized to PVC is, in itself, very simple. There are a couple of other more serious concerns. First, PVC can not be used for water supply inside the home. The second problem has already be mentioned. Galvanized pipe typical has about a 40 year lifespan. It may look very good on the outside, be is almost certainly rusted and corroded on the inside which not only cuts down the water flow, it weakens the pipes and serious leaks are in your future...near future. You should be planning a complete repipe of you home ASAP. I would advise copper. A few might recommend CPVC, but it's still a plastic pipe and except where water content would be a problem with copper, I would not seriously considered it. A complete repipe job is usually too big a job for DIY.

If you want to add pvc to the old pipe heres how, use a galvanized couplin and get a male pvc fitting, clean the threades on pvc with cleaner then put some pvc glue on the threades hand tighten the run pvc, everyone here may not agree but I've done it, it will work but this is after you take the cap off and make sure there is plenty of water coming from the pipe, this is my personal opinion based on what i have done, If someone here does not agree please keep your rude comments to yourself, you ask what would work with this and this will work

There's no argument that this will couple galvanized to PVC and as long as we throw out code books and not concern ourselves with the wisdom of using 80 year old galvanized pipe, this is a perfect answer.:rolleyes:

Now all we have to do is addess the problem of using PVC for ANY hot water piping, PVC inside a building, and the tendency of PVC male adapters to snap off at the threads, and then we can have a system, not a good system, but a system, nevertheless.

well heres what my plan was. I have to go about 3-4' to the right and then straight down to the sink. the plugs are recently place into the elbows that I would be tying into. With in the last 3 years when a new water heater was installed. Ive never worked with galvanized but would it be better to just use the galvanized? Im planning on replacing all the pipes in the next 1-1.5 yrs. they are in pretty good condition but I want to add a toilet ect and figure may as well do it all.

Sounds like your looking for a temporary fix until the new piping is done. I would modify my previous answers accordingly. Although galvanized pipe is ancient technology for water pipes, for the time you are talking about, it will be fine. Not to say the old stuff won't suddenly decide it's game time, but the new stuff will be OK. PVC, while not legal, would also work OK for a short time on the cold water, but I'd never use it even for a short time for hot water. The biggest problem for a novice installing galvanized is making everything fit. Unless you can just be close, you could be facing a lot of cutting and threading. If close is good enough, you can of find short lengths of pipe at the store or have them cut and thread to your request. I prefer plumbers pipe dope instead of tape on the threads. I'd go with a 3/4" to 1/2" bell reducer then a 1/2" nipple followed by a union. When it comes time to repipe, I strong advise copper. Although it doesn't seem like that big of a job, looks are deceiving. For that reason if no other I'd would urge you to hire a plumber to do the job. You might get it done, but it could take several days.

I assumed that anyone would know to use cpvc for hot water. The male adaptor if not over tighten would not break, that has been my experence. As far as pvc being illegal that not the case here almost every home I've seen has had Pvc (and cpvc) even some new house are getting pvc so don't see how it could be illegal, the person ask how to join the two pipes and i told him if don't agree that's fine. but the bottom line is it will work.

CPVC is legal for interior water lines but not PVC. You may have seen it used, but I would bet it was not done by a professional plumber. PVC can be used for water supply lines that are underground. CPVC requires larger sizes than copper because the ID is less. CPVC while legal is not the preferred medium unless the water is corrosive to copper.