Use of copper pip in the house as a ground may or may not work. I say this because most water feeds to buildings these days are using some form of PVC pipe. You really need to look at where the water comes into your house and see just what type of pipe is coming into the house. Unless you have a really old house, like built in the 50's to the early 70's, my bet is you will find plastic coming from the water company.
Your best bet is to install your own ground system. Hopefully your point of going outside the house is fairly near the electrical meter. You should find a ground rod under the meter with a solid copper wire coming from the meter and going to the ground rod. This is required by the NEC.
Now with that said, let me go back to installing your own ground system. Yes I said system. The use of a single ground rod probably won't provide you with an ideal ground with a resistance of less than 5 Ohms. Generally it takes installing 2 or more ground rods and connecting them together.
Make sure you space the rods out so that they are no closer than twice their length. In other words, if you use 8 foot ground rods, the distance between them wants to be 16 feet. This is due to the cone of influence around each ground rod. If you space them closer, the cones will overlap and you will not gain the full effect of the ground resistance each rod will provide.
The ideal connection between the rods and the solid number 2, tinned wire would be an exothermic weld at each ground rod. The tinned copper wire reduces corrosion much better than just plain old bare copper. Unless your in the electrical service business, you won't have access to this process. Another way would be to use a mechanical compression connection. Again, you would need the crimping tool and the compression clips. So the last, least desirable way would be to just use the bronze grounding sleeves you can get from your local hardware store or a place like Lowe's or Home depot.
Going back to the ground rod at the electrical meter that I mentioned at the start. The NEC (National Electrical Code) provides an exception to a radio facility or telecommunications facility to connect the site grounding system to the electrical service ground. This places them at both the same potential and reduces damage from lightning strikes and surges.
Make sure your antenna systems have surge protection on them that is connected to your ground system. It is also wise to install surge protection on you electrical feeds. Many places put a master surge protection device right at the electrical breaker panel. The shorter the wires are between them, the better. Use no metal sleeves to connect the boxes as these act as a choke to surges. You want the surge protector to do it's job. Then make sure you have a low resistance ground going to the surge protector. Again don't use metal conduit to run the ground wire through.
Hope this gives you something to think about in grounding your equipment.