Water Tank Maintenance Checklist

A backup water tank is only useful if it actually works when the municipal supply fails. Johannesburg Water’s own figures show non-revenue water sitting at 44.8% — a signal of how much stress the network is under — and the city’s reservoir buffer is roughly 27 hours of citywide storage. When pressure drops or supply is interrupted, your tank is the fallback. If it hasn’t been maintained, that fallback may let you down.

This checklist is written for Johannesburg homeowners with tank-and-pump backup systems. It covers what to check, how often, and what warning signs to act on before they become expensive.

Monthly Visual Inspection

Once a month, spend five minutes looking at the system with fresh eyes.

• Tank exterior: Look for cracks, bulges, discolouration, or pooling water around the base. Hairline cracks on polyethylene tanks often appear near fittings first.
• Inlet and outlet fittings: Check for weeping joints or mineral deposits, which indicate a slow leak.
• Float valve (if fitted): The float should sit correctly and the valve should seal fully when the tank is at capacity. A valve that runs constantly wastes water and can overflow.
• Overflow pipe: Confirm it is clear and directed away from the foundation.
• Vent or lid seal: The lid should close firmly. Gaps allow insects, debris, and light in — light encourages algae growth.

Note anything unusual and revisit it the following week. Most problems are slow to develop and cheap to fix early.

Pump and Pressure System Checks — Every Three Months

The pump is the most mechanically complex part of the system and the most expensive to replace. Borehole pumps typically cost R15,000–R35,000 installed; even a standard pressure pump for a surface tank system represents a meaningful investment.

• Run the pump briefly and listen. Unusual grinding, rattling, or a pump that cycles on and off rapidly (short-cycling) points to a waterlogged pressure vessel or a worn impeller.
• Check the pressure vessel pre-charge. Most systems have a bladder-type pressure vessel. The air pre-charge should match the pump’s cut-in pressure — confirm the correct figure with your installer’s documentation, as it varies by system.
• Inspect the pressure switch contacts for corrosion, especially in outdoor or semi-exposed installations.
• Test the non-return valve. If the pump refills the tank slowly after demand, or if you hear water draining back into the tank when the pump stops, the non-return valve may be failing.
• Check electrical connections and the isolator switch. Loose connections in an outdoor environment corrode faster than most people expect.

If you are not comfortable working around electrical components, this part of the checklist is one for a qualified installer or electrician.

Valve and Pipework Inspection — Every Six Months

Valves are often ignored until they fail at exactly the wrong moment.

• Exercise all isolation valves. Turn them fully off and back on. A valve that hasn’t moved in a year may seize or fail to seal properly when you need it.
• Check gate and ball valves for leaks at the packing gland and body.
• Inspect UV-exposed pipework. HDPE and PVC pipe both degrade under direct sunlight over time. Look for brittleness, cracking, or discolouration on any above-ground runs.
• Confirm the bypass arrangement (if your system has one) operates correctly. You should be able to switch between municipal and tank supply without fumbling in an emergency.

Tank Cleaning — Every Six to Twelve Months

This is the step most homeowners skip, and it matters. Sediment accumulates at the base of the tank, biofilm can develop on the interior walls, and in tanks without proper UV-inhibited liners, algae can take hold. None of this is visible from the outside.

The cleaning process involves draining the tank fully, scrubbing the interior walls with a food-safe brush (no solvent-based cleaners), flushing the sediment out through the drain point, and rinsing thoroughly before refilling. The detail of each step — including safe disinfection practice — is covered in the guide on cleaning a water tank, which is worth reading before you start.

For drinking-water or cooking use, SANS 241 (2024 edition) is the South African standard for water quality. If your stored water is used for drinking, consider periodic testing by an accredited laboratory rather than relying on appearance alone.

If your tank or pump is due for a service and you're not sure your current installer is giving you a fair price, it helps to have a second opinion. Compare 3 free quotes — vetted installers, no obligation.

Seal and Lid Integrity — Every Six Months

The lid, lid gasket, and any inspection hatches are the tank’s first line of defence against contamination.

• Inspect rubber gaskets for cracking, compression set (the gasket has flattened and no longer seals), or mould growth in the groove.
• Check locking mechanisms. Tanks with children around should have secure lids. A lid that sits loosely is also a safety and contamination risk.
• Confirm the vent screen is intact. The vent allows pressure equalisation but should be screened to exclude insects and rodents.

Replacement lid gaskets for most common tank brands are inexpensive and available from plumbing suppliers. Replacing a gasket takes minutes; contaminating a full tank costs far more in time and water.

Annual System Review

Once a year, step back and assess the whole system rather than individual components.

Item	What to assess
Tank capacity	Is it still adequate for your household’s needs? South Africans use around 237 litres per person per day on average — use this as a rough guide when sizing storage.
Pump age and condition	Most surface pumps have a service life of five to ten years with proper maintenance; confirm with your installer.
Filter elements (if fitted)	Pre- and post-tank filters need element replacement on a schedule — check the manufacturer’s recommendation.
System integration	Does the system switch over correctly and without manual intervention?
Installation records	Do you have a record of installation date, installer details, and warranty documentation?

The broader context — how tank systems fit into a full backup water strategy — is covered on the backup water systems pillar page, which is worth revisiting if your setup is more than two or three years old.

If your annual review turns up more than minor issues, getting quotes now — before a failure — gives you time to compare properly. Get installer quotes — vetted suppliers, no obligation.

When to Call a Professional

Some maintenance tasks are straightforward DIY. Others carry risk — either to the system, to water quality, or to personal safety around electrical components and elevated structures.

Call a professional if:

• The pump is short-cycling and you can’t identify the cause
• You find internal tank damage, including cracks at fittings or delamination of the liner
• Pressure at the tap has dropped noticeably without an obvious explanation
• You’re planning to use stored water for drinking and want the system certified or tested
• Any electrical component shows signs of corrosion or heat damage

For most homeowners, professional servicing once a year — combined with the monthly and quarterly checks above — is a reasonable baseline. What that costs will vary depending on system complexity and installer rates, so confirm via quotes before committing.