Low pressure on every station

What has gone wrong

Every station is weak. Heads barely rise, throw is short everywhere, and it is the same on all of them. That last part is what makes this different from uneven coverage — uneven means the heads, but uniformly weak means the supply.

The usual causes, roughly in order:

• A blocked filter. Bore systems have an inline filter and it silts up. This is the one you can fix yourself.
• A partly closed isolating valve. Somebody wound it back and never wound it forward.
• A main-line leak. Water going into the ground before it reaches the sprinklers.
• The bore or the pump. Lost prime, a worn impeller, a fouled bore screen, a failed pressure switch or a waterlogged pressure tank.
• Too many heads on one station, if this has been true since the system was installed rather than something that changed.

Why this happens in Perth

Bore water is why the filter is first on that list. Perth's domestic bores abstract around 90 gigalitres a year — roughly 22% of the groundwater used across the metro — and that water arrives carrying fine sand and dissolved iron. The sand goes into the filter. The iron feeds iron bacteria, which build an orange sludge that blocks filters and fouls bore screens far faster than sand alone would.

So a Perth bore system's filter is not a set-and-forget component. It is a consumable, and a great many "the pump is dying" calls are a filter that has not been cleaned in three years.

Then the ban. Three months of standing still from 1 June to 31 August is exactly how a pump loses prime and how sediment settles and consolidates. Pumps that ran fine in May do not always come back on 1 September.

Is this a DIY job?

No, and we are not going to pretend otherwise. The filter check below is free and it is worth doing before anything else. Past that, low pressure across a whole system is the bore, the pump, the mains supply or a main-line leak — and every one of those is either mains-powered, under pressure, or buried.

There is nothing here you can safely test past the point above. Mains-powered equipment, bores and pumps are all outside what anybody should be talking you through over the internet.

Your next step: get a Perth reticulation repairer to look at it. Tell them what you have already ruled out — it saves them time and it saves you money.

Three free checks — do these before you ring anybody

One — clean the filter. If you are on bore water there is an inline filter, usually a clear or grey canister somewhere between the pump and the valves. Turn the system off, unscrew the housing — there is often a bleed button on top to release pressure first — lift out the cartridge or screen and look at it. If it is orange, brown or packed with sand, rinse it out and put it back.

This one check resolves a good share of low-pressure complaints on Perth bore systems, and it costs nothing. If the cartridge is a paper element rather than a washable screen, it is a replacement part and a cheap one.

Two — check every isolating valve is fully open. Follow the line from the tap, the meter or the pump and open every valve you find fully. A quarter-turn ball valve left at 45 degrees looks open and is not.

Three — is the pressure low at the tap too? Turn on an ordinary garden tap and see. This splits the problem cleanly in two, which is the most useful thing you can tell a repairer:

• The tap is fine but the retic is weak — the fault is between the supply and the sprinklers. Filter, isolating valve, or a leak in the retic main line.
• The tap is weak as well — the fault is the supply itself. On scheme water that is a job for the water utility. On bore water it is the bore or the pump.

And look for the leak. Walk the yard with the system running and look for a patch that is wetter, greener or softer than everything around it, especially along the line between the pump or meter and the valves. A main-line leak is under pressure whenever the system is on, and it will show on the surface eventually.

Where this stops being DIY

If the filter was clean, the valves are open, and the tap is weak too, then it is the bore or the pump — and that is where we stop.

Do not work on a bore pump. Not because it is complicated, but because of what it is: a mains-powered motor, in and around water, usually with a pressure vessel that stores energy even after the power is off. Priming, impellers, pressure switches and tank bladders are all trade work.

Do not go into the bore. Bore screens, casings and submersible pumps need equipment to pull and specific knowledge to put back. Getting it wrong can silt a bore up permanently, and that is a much more expensive problem than the one you started with.

A main-line leak is a dig-and-repair job under pressure. If you have found the wet patch and you can isolate the water, it is not beyond a competent person — but if you cannot shut it off, or the line is rigid PVC, get somebody in.

Get a repairer to look at it, and tell them exactly what you have already ruled out: filter cleaned, valves open, and whether the tap pressure is good or bad. That last answer alone saves them half the diagnosis.

What it costs

Cleaning the filter and checking the valves: nothing, and it is the answer more often than people expect on bore systems.

A replacement filter cartridge: cheap, and unverified on current Perth pricing. Buy two while you are there and change it annually rather than when the pressure drops.

Pump and bore work: we have not verified rates and the range is wide — a re-prime is a small job, an impeller or a pressure tank is a middling one, and a submersible pull is a big one. Get two quotes and ask each to say what they think it is before they come, based on what you tell them.

One thing worth asking directly: whether they think the pump is worth repairing or replacing. On an old pump the repair is sometimes most of the replacement.

Common questions

Why is my reticulation pressure low on every station?

On a Perth bore system, most often a blocked filter — bore water carries fine sand and iron that silt it up. Cleaning it is free and worth doing before anything else.

How do I tell whether low retic pressure is the pump or the system?

Turn on an ordinary garden tap. If the tap is fine but the retic is weak, the fault is between the supply and the sprinklers. If the tap is weak too, it is the supply, the bore or the pump.

Can I fix a bore pump myself?

No. A bore pump is a mains-powered motor in and around water, usually with a pressure vessel that stores energy even with the power off. Priming, impellers and pressure switches are trade work.