The honest answer is that it depends, and anyone who gives you a fixed number without asking about your tank is guessing. The interval for a villa in Sharjah is set by three things: how big the tank is, how many people are putting water into it, and whether it has ever been properly cleaned rather than just pumped. Get those three right and the schedule almost writes itself.
This guide walks through each factor, shows how to estimate your own interval, and lists the signs that tell you the tank is already overdue.
First: is it a septic tank or a holding tank?
In everyday use in Sharjah, "septic tank" covers two quite different things. A true septic tank lets liquid drain away through a soakaway while solids settle and break down, so it fills slowly and mainly needs the sludge removed. A holding tank is sealed: nothing drains away, so every litre that goes in has to be pumped out. Many villa tanks in Sharjah are, in practice, sealed holding tanks, and they fill far faster than owners expect.
If you are not sure which you have, the rate at which it fills will tell you. A sealed tank fills in proportion to the household's water use; a tank with a working soakaway fills much more slowly. We cover the distinction in more detail in Sewage tank vs septic tank: what's the difference?
The three things that set the interval
- Tank capacity. The usable volume, in gallons or litres. It should be on the building drawings or known to whoever built the tank. Usable capacity is less than design capacity once sludge has built up.
- Occupancy. How many people live in the house, including domestic staff, and whether that changes for parts of the year.
- Water habits. Laundry, long showers, a kitchen that runs all day and a garden hose that drains into the system all add volume that toilets alone do not.
There is a fourth factor that quietly overrides the other three: whether the tank has ever been cleaned. A tank that has only been pumped out keeps a layer of settled solids that grows every year. The tank looks empty after each visit, but its usable capacity shrinks, so the interval between visits gets shorter and shorter. If your tank seems to need emptying more often than it used to with no change in the household, that is almost always the reason.
How to estimate your own interval
For a sealed tank, the arithmetic is simple. Take your household's daily water use — your SEWA water bill shows consumption for the billing period, so divide it by the number of days — and compare it with the tank's usable capacity. Capacity divided by daily use gives the number of days until the tank is full. Book the tanker comfortably before that.
As a purely illustrative example: a household using 1,000 litres a day into a tank with 10,000 litres of usable space has about ten days before it is full, so a collection every week would be the safe interval. Your own numbers will differ; the method is what matters. If you do not know your tank capacity, tell us when it was last emptied and how many people live there, and we will work backwards from how full it is on the first visit.
For a tank with a working soakaway, the liquid drains and the interval is set by how quickly solids accumulate, which is slower and harder to calculate. The practical approach is to have the sludge depth checked when the tank is emptied and let that guide the next visit.
Signs you have already waited too long
- Sinks, showers and floor drains emptying slowly
- Gurgling from toilets when water runs elsewhere in the house
- A sewage smell in the garden or around the tank cover
- Wet ground or pooling water above the tank
- Sewage backing up into the lowest toilet or drain
Any one of these means the tank is close to full. Two or more means call today. Our septic tank service page lists what happens on the visit, and if the tank has already overflowed, the emergency drainage page explains what to do while the tanker is on its way.
Set a schedule rather than waiting for the smell
The villas that never have a problem are the ones on an agreed interval. Once the tank has been emptied and cleaned properly, we can suggest a frequency from its size and your household, and the tanker simply arrives before the tank is full. If the household changes — guests for the summer, a new tenant — the interval changes with it. Call AL NISR DRAINAGE on +971 54 246 3788 to set one up, or read more about our residential drainage service across Sharjah.