The plumbing is the most important part of a household water system because without proper devices your water system in home may turn into a nightmare.
There are some plumbing supplies that are necessary for each household for creating normal water system.
Some of these are: plumbing pipes, plumbing fittings, plumbing brassware, water saving devices (mechanisms or taps that won't let your water stay running over certain period of time), plumbing wastes and traps, ventilation products (so that you wouldn't have bad smell around the house), water valves and plumbing valves and finally, hard water treatment products for protecting water boilers and washing machines from scale.
Most of the times, plumbing suppliers already offer technically advanced products for your kitchen and bathrooms, nowadays there are many choices of pipe materials, shapes and lengths.
Because of the competition between plumbing suppliers, the delivery dates are extremely short and companies try to make people also use their installing service so that the devices would be installed properly. Usually some benefits are offered for using particular company's products.
Plumbing can also be made without a help from the plumbing companies. Then you only need the supplies that are listed above and a handyman who has done this kind of job before.