Suggestions by Peter Weddell, owner/operator of Qld Home Buyers Inspection Service:
These fittings a common choice for a handyman because of ease of use, without the need for specialist tools to connect them. Not the sort of plumbing connections you would want in your roof or hidden within walls and/or the sub-floor !
This is a pipe and fitting system designed for use with low pressure irrigation and water tanks only, in this case it had been connected to the mains water, below a northern suburb house.
It is only a matter of time before the connections burst. This is the last thing you would want while you are away on holidays or in the early hours of a morning, imagine the damage it would cause!
Photo of Rehau brand of pipe and fitting. These are a much more reliable choice of fitting also the choice of most licensed plumbers. These fittings require a special tool for securing the joints.
Inferior plumbing-Brisbane, important note:
PVC water pipes are prone to damage from vermin. If this happens I would strongly advise replacing the PVC pipes with copper.
PVC over copper are less likely to have water hammer, cheaper and much easier to fit. Copper over PVC, much more durable for the long term and far less likely to leak, if properly secured and fitted by a qualified plumber.