A conservancy tank is a sealed tank with no outlet. Unlike a septic tank, it doesn't feed a French drain, so everything that goes down your drains stays inside until a vacuum truck takes it away. That means far more pump-outs: one ratepayers' group quotes monthly emptying for a 5,000 litre household tank.
How is a conservancy tank different from a septic tank?
A septic tank treats. A conservancy tank only stores.
The City of Tshwane's Sanitation By-laws spell it out. A septic tank is "designed to receive sewage and to effect the adequate decomposition of organic matter in the sewage by bacterial action". A conservancy tank is "a covered tank which is used for the reception and temporary retention of sewage and which requires emptying at intervals".
In plain words: a septic tank lets solids settle and sends the liquid on to a French drain, where it soaks into the ground. A conservancy tank has nowhere to send anything. It fills up, and then it has to be emptied.
| Septic tank | Conservancy tank | |
|---|---|---|
| What it does | Settles solids, bacteria break them down | Holds everything until it's pumped out |
| Where the liquid goes | Out to a French drain or soakaway | Nowhere. It stays in the tank |
| How often it's emptied | Depends on sludge build-up, tank size and use; published guidance runs from 12 to 18 months (one operator) to 3 to 5 years | As often as it fills, monthly in one published example |
| Needs council permission | Yes | Yes |
When does the council ask for a conservancy tank?
A conservancy tank is usually the answer when the ground can't take a French drain.
Both metros decide case by case. Tshwane's by-laws say the City "may, at its discretion" permit a French drain, looking at the amount of effluent and "the nature and permeability of the soil". Johannesburg's Water Services By-laws use almost the same test.
A summary of the national drainage standard, SANS 10400-P, says a French drain should only go where a percolation test passes in 30 minutes or less, a figure the designer checks for your site. That's a timed check of how fast water drains into a test hole. Slow, clayey soil fails that test, and a conservancy tank is the usual fallback.
The council also sets the tank itself. In Tshwane, the Engineer may permit a conservancy tank and prescribes its capacity and level. Johannesburg's by-law says the tank must be of the capacity, material and position the Council requires. A SANS 10400-P summary adds that it must be watertight, reachable by a vacuum tanker and sited near the driveway.
So don't buy a tank first and ask later. Get the size and position from your municipality's plans office, or from the plumber who submits your plans.
How often will a conservancy tank need emptying?
A conservancy tank fills at the same speed your household sends water down the drain. Every shower, flush and load of washing ends up inside it.
That's why the numbers look so different from a septic tank. The Noordhoek Ratepayers' Association in Cape Town describes a 5,000 litre conservancy tank "which is cleaned every month". For a septic tank, how often depends on sludge build-up, tank size and use; one Gauteng operator's guidance is every 12 to 18 months under normal use.
Three things stretch the time between pump-outs:
- Keep rainwater out. Tshwane's by-laws say no rainwater or stormwater may go into a conservancy tank. A gutter or yard drain tied into it fills the tank for free.
- Fix leaks. A toilet that runs all night is sending clean water straight into a tank you pay to empty.
- Book before it's full. The same ratepayers' group advises asking for a cleaning at least a week before the tank will be full.
What does it cost to run a conservancy tank?
Every pump-out is paid for, so the yearly cost is simple arithmetic: the price per load, times the number of loads.
Published Pretoria septic pump-out prices sit around R2,300 to R3,300 for a 3,000 litre tank, according to a quote broker's price guide. A national cost guide gives R1,500 to R3,000. Your quote depends on tank size and access.
Now compare. A septic tank might need that once every 12 to 18 months. A conservancy tank emptied monthly needs it twelve times a year. That gap is the main reason people ask whether they can switch to a septic tank and French drain, which only the council can approve.
Don't count on the municipality to do it for you. Tshwane's by-laws say the running and maintenance costs of on-site sanitation are the owner's, and that the City "will not, under normal circumstances, render such operation and maintenance services". Johannesburg's by-law does provide for Council removal of conservancy tank contents on a schedule it sets, charged by the volume removed. Ask Joburg Water whether that applies to your property.
What about the tank itself? We haven't found a reliable published price for a new conservancy tank in Pretoria, so we won't guess. Ask an installer for a written quote that covers the tank, the digging and the plan approval.
What to check when the truck comes
- Litres on the slip. The pump-out slip should show the volume taken. If it's well above what your tank holds, ask how the volume was measured, and note any disagreement on the slip.
- Where it's going. In Tshwane, anyone carting sewage must make sure the place they offload it is authorised to accept it. It's fair to ask where your load is going.
- A way in. Where a removal vehicle has to drive onto the property, Tshwane's by-laws ask for a hardened roadway at least 3.5 metres wide. Gates must be no narrower than 3.5 metres.
- Hose reach. One Pretoria operator asks for access to the manhole within 30 metres of the truck. That's its access condition; other trucks differ.
Ask for a conservancy tank pump-out
Tell us where you are and what you need. We pass your request on. A vetted local septic operator in your area calls you to confirm the price and a time.
Prefer to talk? Call 060 086 9889. If we miss your call, leave a message and we'll call you back.
Sources for the figures on this page
- Septic tank and conservancy tank definitions (Tshwane) archive.opengazettes.org.za
- Septic tank needs prior written consent (Tshwane, s7(1)); French drains at the City's discretion, soil permeability (s8); Engineer permits conservancy tank and sets capacity and level (s10(1)); no rainwater or stormwater into a conservancy tank (s10(2)); 3.5 m roadway, 4 t wheel load, 3.5 m gateways (s10(5)); offload only at an authorised facility (s11(4)); owner bears operation and maintenance, City will not normally render it (s38) archive.opengazettes.org.za
- Disused tank removed or filled (Tshwane) www.tshwane.gov.za
- Johannesburg: septic tank needs prior written permission (s65); French drain at Council's discretion, soil permeability (s66); conservancy tank capacity, material, position per Council (s67); Council removal on its schedule (s69); fees by volume removed by vacuum tank (s70); disused tanks removed or filled (s71) openbylaws.org.za
- French drain only where percolation test is 30 minutes or less; conservancy capacity set by local authority; watertight, vacuum-tanker access, near the driveway sitekiln.co.za
- 5,000 L conservancy tank "cleaned every month"; request cleaning at least a week before full nrpa.org.za
- Septic pumping every 12 to 18 months under normal use septictankpumpinggauteng.co.za
- Septic tanks every 3 to 5 years www.rototank.co.za
- Pretoria pump-out R2,300 to R3,300 for a 3,000 L tank frenchdrain.co.za
- Pump-out R1,500 to R3,000 kandua.com
- Conservancy tanks cheaper to install, ongoing pumping costs calcamite.co.za
- Manhole access within 30 m of the truck suckaseptic.co.za