If a home has been unused for a week or more, do not make the first glass from stagnant plumbing your restart test. Flush the plumbing methodically, inspect the treatment equipment and follow each manufacturer’s restart instructions before returning the system to normal use.
Why an unused home needs a restart
Water can remain in service lines, hot-water systems, flexible hoses, filter housings and appliances while a property is vacant. Public tap water is treated, but it is not sterile. CDC guidance notes that waterborne germs can grow in building plumbing when water sits still, especially where temperatures and disinfectant residuals become favourable.
Stagnation can also increase contact time between water and plumbing materials. NSW Health advises using the cold tap for drinking and cooking because hot-water systems may contain higher concentrations of dissolved metals and minerals.
This does not mean a typical Australian mains-water home becomes dangerous every time its owners travel. It means the first-use condition differs from normal turnover and deserves a controlled reset.
Before opening every tap
Walk through the system first:
- Look for leaks, cracked housings or water around appliances.
- Confirm isolation and bypass valves are in their intended positions.
- Check whether a scheduled cartridge or UV-lamp service fell due while away.
- Review the filter, RO, UV and hot-water manufacturer’s restart instructions.
- If power was isolated, restore equipment only in the specified sequence.
If the property uses rainwater, bore water, a pump, storage tank or disinfection equipment, apply the site-specific operating plan. A private-source system may need checks that a mains-water checklist cannot cover.
A practical mains-water flushing sequence
CDC advice for a home unused for a week or more is to run cold water from all faucets and showers on full for at least two minutes, then run hot water until it reaches its maximum temperature. It also says to follow the water-heater manufacturer’s flushing instructions because systems differ.
For a typical home, a sensible sequence is:
- Remove obvious splash-sensitive items and ventilate bathrooms.
- Start with cold water at a suitable outlet and flush until it is cold and the supply is stable.
- Run other cold taps and showers, avoiding aerosol exposure if there is any known microbiological concern.
- Flush toilets and operate appliances according to their manuals.
- Run hot outlets until the water is fully hot; do not drink from the hot tap.
- Restart and flush each treatment device using its own manual, including any discard volume.
- Clean tap aerators or showerheads if the manufacturer or local authority recommends it after works or debris.
The CDC’s two-minute figure is a general household action, not proof that every large building, long service line or private-water installation is fully refreshed. If the property has an unusual layout, calculate the plumbing volume or seek site-specific advice.
Filters need their own instructions
Do not assume flushing the tap also completes a filter restart. Different devices may require different actions:
| Equipment | Restart question to check |
|---|---|
| Carbon cartridge or vessel | Required flush volume; overdue replacement; unusual odour or fines |
| Reverse osmosis | Tank drain/refill instructions; sanitisation schedule; membrane preservation after long shutdown |
| UV disinfection | Lamp, sleeve, alarm and power status; required prefiltration and flow |
| Refrigerators and ice makers | Discard volume or batches specified by the appliance maker |
| Hot-water system | Manufacturer’s restart and flushing procedure; temperature and safety controls |
Never improvise chemical sanitisation concentrations. Use the equipment maker’s procedure or a qualified service provider, particularly where a membrane, resin, UV chamber or pressurised vessel could be damaged.
After a pressure loss or plumbing work
A holiday is not the only restart event. CDC recommends flushing after loss of water pressure and after water has been shut off for repairs. Local utilities may issue more specific advice following a main break, boil-water alert or planned works. Those notices take priority over a general blog checklist.
If water is discoloured, contains persistent particles, has a strong unusual odour, or the utility has issued an advisory, stop and check the current local instructions. Boiling deals with susceptible microorganisms when officially advised; it does not remove dissolved chemicals and can concentrate some of them as water evaporates.
When testing or service is the better answer
Arrange qualified assistance when:
- private bore or rainwater has been unused or the disinfection barrier failed;
- there was flooding, backflow, pest entry or tank contamination;
- an RO unit was shut down outside its preservation instructions;
- UV alarms, pump faults or pressure anomalies remain;
- water quality does not normalise after the recommended flush;
- a vulnerable household member’s health advice requires additional precautions.
Water Analytics Australia can help review a home filtration system and build its specific restart and maintenance steps into the handover. The best checklist is the one that names the actual valves, cartridges, alarms and discard volumes in your home. For routine checks after restart, use our guide to confirm whether a filter is still working.