For sure treat the symptom (leaks) but I'd look to cure the disease or you'll continue to have problems.

Have you checked the PH of your water?

The greenish color is "patina", which is basically just a layer of copper sulfate on the exterior of the pipe. Generally Patina is not a problem and in the art world it is highly desireable. In fact, patina is what gives the statue of liberty that famous green color.

The immediate cause for concern is the fact that you have had numerous leaks on that line. That is a primary indication that you are in the early stages of line failures from "pin holes", which are caused by a high PH ( acidic) level in your water. If that is the case eventually you will have to replace all the copper pipes in the house, but I would not panic at the moment. You may want to begin budgeting for a whole house piping job in the future, but for now I would definitly suggest you change all accessible pipe any time you have reason to open the walls.

AS justaluker has already mentioned, you should get your water PH level tested. If it proves to be acidic you may want to consider some type of water treatment to lower the PH.

Now I am sure that some will argue that you should switch from copper to CPVC or PEX pipe because it will tolerate the high acidic level, but in my humble opinion, if their is anything in your water that threatens the integrity of the pipes, I have to wonder what the long term health effects are of drinking, cooking and bathing with that water? It makes much more sense to me to correct the water condition rather than search for a pipe material that will tolerate it.

Is there some type of test kit I can buy or should I get the water PH tested professionally.

The house is about 37 years old and my neighbor has had similar leaks so could it just be the age of the pipes?

The vertical pipes look fine just the horizontal ones have green spots at least the ones I can see right now.

Thanks for the information I'll definitely test the PH of the water.

You should be able to buy a PH test kit at any pet store that sells fish or they may test a water sample for you.

Municipal water suppliers are required to maintain a testing lab where they test the municipal water supplies numerous times per day.

In most jurisdictions you can take a sample to their lab and they will perform a complete water quality test for a very moderate fee.

In some communities you can actually get a water sample kit at the Health Department or some local True Value or Ace Hardware stores. You take the sample bottle in the kit home, get a sample and return it to the store to be forwarded to the lab.

From the description given, which includes your neighbor having similar problems, it is most likely acidic water.

I suggest a third party (independent) lab test your water, not because you can't determine pH by the other methods suggested, but because you will most likely have to treat the water and a test gives quantified targets.

Switching to CPVC or PEX will solve the piping corrosion but will not help faucets, mixers, relief valves etc., all metallic components.
Neutralizing will be in order, but that increases hardness...so the test will reveal existing hardness and aid in selecting a softener if needed.

As for the acid water affecting health, I don't think so. We drink acidic things daily...OJ, coffee, soda etc.
On the other hand, drinking whatever solvate comes from the water system (remember when they banned lead solder?) could be, and argues further for a potable water test.

Either pH or a change to lower Total Dissolved Solids under the newer EPA rules.

The problem has shown up in a number of systems, and the 'solution' to over-cleaning the water has been to add orthophosphates back in to limit the corrosion and allow the formation of the protective layer inside the copper pipes that the cleaner water strips out.

"....orthophosphates...."

Sounds like you may be describing Tucson back in '93 when CAP water was introduced to household supplies. Lot's of trouble. Added chloramine to a level that started ruining pipes, heaters, and other household machinery. Then added zinc orthophosphate to attenuate that problem. Before they got around to it they were even blowing up their own mains. It was a very costly period for everyone down here. Millions in damages.

Throughout the entire period they continually repeated the mantra "....don't worry, it's perfectly safe to drink." I didn't care. Had pre-filter, softener, and RO at my place. However, I can tell you the exact day the CAP water hit. You should have seen my 30-micron pre-filter. I had to change that thing every two weeks.

The EPA water quality folks did not even talk to the EPA in house corrosion folks when they drafted the newest water standard.

This has caused a rash of problems form the 'cleaner' water, one of which is pin hole leaks in copper lines.

Very pure (clean) water is actually very aggressive and corrodes piping badly.

It is used in semiconductor fabrication, but they learned very quickly (the water reacted with the pipes and was no longer clean enough fr its purpose) and switched to plastic for transport and delivery.

The film that forms on the inside of copper pipes is what protects us from excessive copper in the water supply.

New copper pipes have killed many a salt water aquarium.
Old copper pipes with their protective film are not nearly as much of a problem.

The reduced TDS standard appears to be the main culprit in stripping away the protective film, and not allowing it to form adequately.

In goes the orthophosphate to try and limit corrosion.