Plumbers and drainers in the Northern Territory are licensed by the Plumbers and Drainers Licensing Board under the Plumbers and Drainers Licensing Act 1983. A licence as a plumber, a drainer, or a plumber and drainer lets a tradesperson contract for that work on their own account and supervise others; the Act calls the holder an advanced tradesman, and qualified people working under them hold a journeyman registration card. The Act doesn't require licence numbers in advertising, but section 44 says a plumber must produce their current licence or card when the owner or occupier asks, and the Board keeps a register of holders. Certifying work sits under a different law. The Building Act 1993 makes certifying plumber a category of building practitioner, registered by the Building Practitioners Board, and section 25 says a company carrying out that function must have its registered individual's name in all of its advertisements relating to it. The rules for builders and electricians are on our page for Darwin tradies, and the Board that issued your licence can tell you exactly what applies to you.
The Building Regulations 1993 adopt the Plumbing Code of Australia, Volume Three of the National Construction Code, along with the Department of Health's Code of Practice for Wastewater Management, and where the two conflict the wastewater code prevails. Minor plumbing maintenance, such as replacing a component with a similar one, is exempt, though that exemption doesn't extend to drainage work. Plumbing or drainage done on its own, rather than as part of other building work, needs no building permit or occupancy certification provided notice reaches the Director of Building Control within 7 days of the work (the regulations don't count weekends or public holidays), with a certificate from the building practitioner that it meets the code. A plumber or drainer must also notify the Director when drainage work is complete, before it's covered up, and only a certifying engineer (hydraulic) may design or certify a performance solution. A homeowner doesn't need any of that by regulation number; a sentence saying you look after the notice and certificate is enough, if that's how you work.
Power and Water Corporation, a Territory government-owned corporation, supplies Darwin's water and sewerage, and plumbing or drainage services vested in it are left out of the Building Act's definition of building work. The Water Supply and Sewerage Services Act 2000 bars anyone from connecting to or working on its water or sewerage infrastructure without its written approval. Pipes on a property that carry sewage to its sewer, and don't belong to it, are the house drain: Power and Water can direct an owner in writing to repair one it believes is letting stormwater in, and the owner pays. Where tree roots have damaged or blocked its pipes, it can require the owner of the land where the tree grows to remove the tree or the roots responsible and repair the damage at their own cost, and an owner who keeps the tree must undertake in writing to pay if the same roots cause trouble again. With Darwin averaging around 1,800 mm of rain a year, most of it from December to March, a drains page that explains that rule in a sentence is worth having. Discharging trade waste to the sewer also needs Power and Water's written approval under its published trade waste code, which is worth a line from any plumber fitting out cafés in the city or workshops in Winnellie, Yarrawonga and Pinelands.
Beyond Palmerston, Litchfield Municipality covers 2,903 km² from Howard Springs and Humpty Doo to Berry Springs and Darwin River. Its council says the majority of properties provide their own water from a bore, that Power and Water's responsibility ends at the meter for those on town water, and that breaks and leaks on private lines, the "spaghetti lines" some of which run more than a kilometre, are the landholder's to fix; any work in a road reserve needs the council's approval. It tells owners to unplug the bore in severe electrical storms because lightning can damage it, and says septic tanks should be cleaned every three to five years and kept clear of stormwater and rainwater tank overflow. Where no Power and Water sewer is available, on-site systems are installed to the Code of Practice for Wastewater Management, and none can be sold without a product approval from the Chief Health Officer. One quirk of the licensing Act matters out here: it lets someone without a licence work on an installation connected to a bore on the same land, and install irrigation that isn't connected to the Territory's water supply. A rural owner comparing quotes may not be comparing licensed plumbers, so stating your licence and number counts for more on acreage, not less.
We're an Adelaide team on Hutt St and we haven't built a site for a Territory business yet; our plumbing client is M.J. Debney in Queensland. Everything runs by phone and email. Darwin and Adelaide share Australian Central Standard Time, but the Territory doesn't use daylight saving, so from October to April Adelaide runs an hour ahead and we book calls in Darwin time. The rules above come from Territory legislation and Litchfield Council, so check anything about your own licence with the board that issued it before it goes on your site.