Can I put a water tank against my boundary wall?

Yes, in most cases — but check your municipality's bylaws and your title deed conditions, as some restrict permanent structures within a certain distance of the boundary. Also confirm that the boundary wall itself can handle any incidental load if the tank will be mounted against it, and leave enough gap to access the tank's inlet, outlet and float valve.

How much space does a slimline tank actually need?

A typical slimline tank is around 500–750 mm deep and varies in width depending on the volume, so a 2,000-litre slimline might occupy roughly 500 mm × 1,800 mm of floor footprint — though dimensions vary by manufacturer. Always check the spec sheet for the exact model before measuring your available space, and add at least 300 mm on each accessible side for pipework and servicing.

Do I need council approval to install a water tank?

Johannesburg bylaws generally do not require a building plan amendment for a small freestanding tank, but a permanent raised stand or any structure attached to the building may trigger approval requirements. Your installer should be familiar with local requirements, and it's worth a quick call to the City of Johannesburg's Development Planning department if you're uncertain.

Will an underground tank work on a small property?

Underground tanks remove the visual and space impact entirely but add significant excavation and installation cost, and they require a pump because there's no gravity head. They can be a good solution where above-ground options are genuinely exhausted, but they are typically the most expensive route and should be confirmed via a detailed site assessment before budgeting.

What's the minimum size tank worth installing?

There's no single right answer, but a tank smaller than around 1,000 litres provides very limited supply buffer — at South African average household consumption rates, even a modest household can exhaust that in a matter of hours. Most installers on small properties recommend starting at 2,000–2,500 litres as a practical minimum, and going larger if the site allows, as the incremental cost per additional litre decreases as tank size increases.

Where to Put a Water Tank on a Small Property

Space is genuinely tight on many Johannesburg stands — a 500 m² plot with a double garage, a boundary wall, and a garden leaves precious little room for a large round tank. The good news is that placement is mostly a problem of geometry and pressure physics, both of which are solvable once you understand the trade-offs. This guide works through the practical options without overselling any of them.

Why placement matters more than most people expect

Where a tank sits determines three things that affect your daily experience: the water pressure you get, how safely the installer can connect pipework, and how easily a technician can service the pump or float valve in two years’ time. Get the location wrong and you end up with a system that technically works but delivers a disappointing trickle at the showerhead, or one where the pump is wedged so tightly against the boundary wall that it takes half a day to replace.

For context on why Johannesburg homeowners are looking at backup storage at all: the city’s reservoir system holds roughly 27 hours of citywide storage buffer, which means a sustained supply interruption can affect your taps faster than most people assume. Having your own storage changes that equation considerably — see the full picture on our backup water systems guide.

The pressure physics in plain language

Gravity-fed systems — where water flows from the tank to your taps without a pump — need the tank base to be at least three metres above the outlet for usable pressure (roughly 0.3 bar, enough for a basic shower). On most small properties that height is only achievable by mounting the tank on a raised stand, which adds cost and requires a structurally sound base.

Most installations on small stands therefore use a pressure pump to push water from a ground-level or below-deck tank. This works well, but the pump adds to the system cost and is one more component that needs maintenance. When you’re comparing quotes, make sure the pump spec is included — backup tank-and-pump systems typically run R20,000–R40,000 for a standard setup, with whole-house configurations around R55,000, though you should confirm actual figures with installers for your specific site.

Side walls and narrow strips

The side passage between a house and a boundary wall is the most common location on a small Johannesburg property — it’s usually underused and already has a path for pipework. The constraint is width: a standard round 2,500-litre tank needs roughly 1.5 m of clearance. If your passage is only 900 mm wide, a slimline tank becomes the practical choice rather than a style preference.

Slimline tanks are taller and narrower than round tanks — typically 500–750 mm deep — and can hold useful volumes (1,000–5,000 litres) in a footprint that fits against a wall. They do cost more per litre of storage than equivalent round tanks, so if you have a wider side yard a round tank will stretch your budget further. Our comparison of slimline vs round water tanks goes through the trade-offs in detail.

When using a side wall, confirm that the pipework route to the house is practical and that an electrician can run a cable to the pump without having to break through tiled surfaces.

Under decks, carports and pergolas

A deck or carport that sits 600 mm or more off the ground can shelter a low-profile tank or a horizontal bladder-style tank. This is useful when you want the tank out of sight, but there are real constraints: the structural load of a full tank (water weighs 1 kg per litre, so 2,500 litres adds 2,500 kg) must be calculated, ventilation matters for pump heat, and you need a hatch or gap large enough to inspect and service the system. If your deck is already built, retrofit access can be expensive.

A carport slab is generally the simpler option — tanks sit directly on the concrete, there’s no overhead load concern, and the structure is usually open enough for easy access.

Not sure which setup fits your specific stand size and layout? Compare 3 free quotes — vetted installers, no obligation.

Basements, utility rooms and garages

If you have a basement or a large enough garage, an indoor installation protects the tank from UV degradation (which shortens the lifespan of plastic tanks over years of direct sun exposure) and removes any aesthetic concern. The pipework run may be longer, which can mean slightly higher installation cost, but the tank itself will last longer out of direct sunlight.

Garages present a practical complication: cars, bicycles and general storage compete for floor space. Measure carefully and account for the pump and associated pipework before committing. A tank placed so a car door can’t open fully will become a daily irritation.

Rooftop tanks — worth considering or not?

On a single-storey property with a flat roof designed for foot traffic, a rooftop tank provides excellent gravity pressure without a pump. On most pitched-roof Johannesburg homes, however, the roof structure is not designed for that kind of point load, and retrofitting structural support is often more expensive than simply buying a pump. Have a structural engineer confirm load capacity before going this route — it’s a short consultation that can save a costly mistake.

Getting the installation right from the start

Once you’ve identified the likely location, the installation process itself has its own considerations — foundations, overflow drainage, first-flush diverters if you’re harvesting rainwater, and compliance with local bylaws. Our step-by-step guide on installing a backup water tank covers what to expect from the process.

Water quality is also worth noting: any stored water that enters your home’s plumbing should meet SANS 241 (2024 edition), the South African drinking-water quality standard, especially if the tank is connected to drinking-water outlets rather than garden or toilet-flush use only.

Ready to move from planning to actual quotes? Get 3 installer quotes for your property — free, no obligation, vetted suppliers.

What to confirm before you decide

Before settling on a location, run through this short checklist with your installer:

Question	Why it matters
Is the ground or slab level and load-bearing?	Uneven or weak bases cause tanks to deform over time
Is there a practical pipe route to the house?	Long or complex routes add installation cost
Can the pump be serviced without dismantling the setup?	Access affects long-term maintenance cost
Is there sufficient electrical supply nearby for the pump?	Adding a dedicated circuit adds to the project cost
Will the tank be in direct sunlight?	UV shortens plastic tank lifespan; shade or UV-stabilised tanks help

The right location on a small property is rarely the obvious one — it’s the spot that balances access, pressure, pipework practicality and long-term serviceability. Taking an hour to walk the site with a reputable installer before committing to a tank size or shape will save you from the most common regrets.