Zip Plumbing Upper Hutt is listed as a hardware store at 33 Park St, Kingsley Heights, Upper Hutt, with a Google rating of 4.6. By its name it is a plumbing business, so it may supply plumbing materials or services as well.
A good hardware or plumbing supplier carries the common fittings, pipe, tools and sealants, and has staff who can tell you which part fits and how it goes together. The most useful tip is to bring the old part, or a clear photo with measurements, since pipe sizes and threads vary and the wrong fitting wastes a trip. Regulars know that trade counters often open early and get busy at the start of the day, that some jobs, such as gas or work on the water supply, must be done by a registered tradesperson in New Zealand, and that it is worth asking about returns before you cut or open a product. Ask for advice on tools and materials suited to your job, and read safety notes on glues and cleaners.
For homeowners and tradespeople in Kingsley Heights and around Upper Hutt, Zip Plumbing on Park St is a well-rated local business to ask about.