Septic tanks under the Saudi code: the numbers an inspector checks
A plain summary of what the Saudi Private Sewage Code says about septic tanks, so you know what to ask for before excavation.
- Code figures in one table
- Single or two-chamber
- Diameters from 1.20 m
- 25-year warranty
We reply within one working hour, Saturday to Thursday.
Is a GRP septic tank permitted?
Yes. The Saudi Private Sewage Code (SBC 702) lists fibreglass among septic tank materials, alongside welded steel and monolithic concrete, and requires the tank to be watertight and built as a single unit.
The code also requires the design of a prefabricated tank to be accepted by the authority, so check your municipality's requirements before ordering.
The code figures in plain words
In flood-prone locations the code requires tanks to be anchored against buoyancy.
| Item | What the code says |
|---|---|
| Chambers | At least two |
| Inlet chamber | At least two thirds of capacity and not less than 1.9 m³ |
| Second chamber | At least 0.95 m³ and no more than one third of capacity |
| Minimum liquid capacity | 2.85 m³ (2,850 L) |
| Liquid depth | At least 750 mm |
| Cylindrical tank diameter | At least 1.2 m |
| Manholes | One per compartment, 600 mm diameter or 0.6 m² |
| Manhole riser | Same material as the tank and integral with it |
| Bedding | 75 mm compacted sand and gravel |
| Tanks in series | Four at most |
| Emptying | When sludge occupies one third of liquid capacity |
What the municipality looks at
The municipal code official issues the permit for a private sewage system and inspects it, and the contractor is responsible for installing it to the code.
Details vary by municipality. In Riyadh, for example, the municipality's project audit form requires adjoining villas to have separate services, including water and sewage tanks.
Sealed holding tanks
A sealed tank with no soakaway is a holding tank in the code's terms, and is approved only where no other private system can be installed on the site.
For non-residential buildings it must hold at least 5 days and no less than 7.6 m³, so tell us the building type when you request a quotation.
Laura septic tanks: single or two-chamber
We build GRP septic tanks with one or two chambers as your municipality requires, at the capacity your engineer sets. Our diameters start at 1.20 m, the code's minimum for cylindrical tanks.
This summary shows what you will be asked about; it does not replace your municipality's or engineer's requirements. Septic tanks carry our 25-year warranty against manufacturing defects, subject to the installation guide.
Frequently asked questions
Does the code allow GRP septic tanks?
Yes. SBC 702 lists fibreglass among septic tank materials, provided the tank is watertight and a single unit.
What is the smallest septic tank allowed?
2.85 m³ of liquid capacity (2,850 litres), rising with the number of building occupants.
One chamber or two?
The code calls for at least two chambers, and your municipality decides what it accepts. We build one or two chambers to its requirement.
When should the tank be emptied?
Whenever sludge reaches one third of the liquid capacity, as the code states.
Can two adjoining villas share a septic tank?
In Riyadh the municipality's project audit form requires separate services for adjoining villas, including sewage tanks. Check your own municipality's rule.
Related pages
Septic tanks
One sealed piece with one or two chambers to your municipality's requirement.
Villas and homes
Cooler water in summer, no rust or algae, and a clear split of who digs and who pours.
Hotels, rest houses and chalets
Capacity for weekend guests, cooler water, and the septic tank in the same quote.
Installation guidance
Our scope, your contractor's scope, and the burial conditions.
Ready for your quote?
Send the type, capacity and city, and we reply within an hour.