uPVC sewer and drainage pipe is the standard specification for wastewater and stormwater networks in Saudi Arabia. 4B Factory manufactures it in Al-Kharj to Saudi Standards SAS 1395/1396 and SASO ISO 4435, in Classes 2–4 and diameters from 110 mm to 710 mm, for gravity sewer lines, surface-water drainage, and sub-soil dewatering across the Kingdom.
Every building, road, residential compound, and industrial estate needs a way to carry wastewater and rainwater away safely. In Saudi Arabia's ground conditions — arid, often saline, with seasonal stormwater that arrives fast and heavy — the underground drainage network has to be corrosion-proof, watertight, and correctly sized. Across municipal sewerage, residential subdivisions, and infrastructure works, unplasticised PVC (uPVC) has become the default material for the job. This guide explains how sewage and drainage piping is selected, classed, and specified for Saudi projects, and how 4B Factory supplies it factory-direct from Al-Kharj.
Why uPVC Is the Standard for Sewage & Drainage
uPVC sewer pipe is preferred for underground drainage because it does not corrode, scale, or degrade in the saline soil and groundwater common across the Kingdom. Unlike concrete or ductile-iron drainage pipe, a rigid PVC sewer line keeps a smooth internal bore that resists blockage, sediment build-up, and root intrusion, and its watertight elastomeric joints prevent both exfiltration of sewage into the ground and infiltration of groundwater into the system.
The practical advantages that make uPVC the go-to material for wastewater and stormwater networks include:
- Corrosion resistance — immune to the hydrogen-sulphide attack that destroys concrete sewer crowns and the rust that pits metal pipe.
- Smooth hydraulic bore — low Manning's roughness coefficient means a better self-cleansing flow velocity and fewer blockages.
- Watertight, leak-proof joints — rubber-ring (elastomeric) seals keep the gravity sewer line sealed under load and groundwater pressure.
- Light weight & fast installation — lower handling, bedding, and jointing cost per metre than concrete or ductile iron.
- Long service life — a design life measured in decades when the correct SAS class and ring stiffness are specified for the burial depth.
- Chemical resistance — tolerant of domestic sewage and many industrial effluents.
Gravity Sewer vs Stormwater vs Sub-Soil Drainage
"Drainage" covers three distinct jobs, and each calls for a different pipe. Getting this split right at the design stage is the difference between a network that self-cleanses for decades and one that silts up, surcharges, or floods.
Gravity foul sewer (wastewater / sewage)
Carries domestic and commercial wastewater downhill to a treatment plant or pumping station. Uses solid-wall uPVC sewer pipe to SAS 1395/1396, sized to the peak sewage flow and laid to a self-cleansing gradient so solids do not settle. This is the classic underground sanitary sewer line.
Surface-water & stormwater drainage
Removes rainwater and surface runoff — critical in Saudi cities where infrequent but intense rainfall can flood roads within minutes. Uses large-diameter solid-wall uPVC (up to 710 mm) for storm sewers and culvert drainage, sized to the design storm return period.
Sub-soil & groundwater drainage (land drainage)
Lowers the water table around foundations, roads, and farmland, and controls the salinity that builds up under irrigation. Uses perforated uPVC drainage pipe with slots or holes that let groundwater seep in — the functional opposite of a sealed foul sewer.
Sewer Pipe Classes & Sizes: SAS 1395/1396 Explained
uPVC sewer and drain pipe is graded by class, which reflects its ring stiffness — its resistance to being crushed by the weight of soil, groundwater, and surface traffic above it. In the Saudi Standard system (SAS 1395/1396, aligned with SASO ISO 4435 for SDR sewer pipe), sewer pipe runs from Class 2 to Class 4, with the heavier class used for deeper burial and heavier surcharge loading. The table below is the specification set a drainage engineer works from.
| Specification | Detail |
|---|---|
| Material | Unplasticised PVC (uPVC / rigid PVC) |
| Standards | SAS 1395 / SAS 1396 · SASO ISO 4435 (SDR sewer) |
| Diameters | 110 mm – 710 mm outside diameter |
| Classes | Class 2, Class 3, Class 4 (by ring stiffness) |
| Joint type | Rubber-ring (elastomeric) socket — watertight |
| Flow property | Smooth bore, low Manning's roughness, self-cleansing |
| Application | Gravity foul sewer, storm drainage, culverts |
Standards compliance is not optional on a Saudi drainage project: sewer and drainage pipe is governed by the Saudi Standards, Metrology and Quality Organization (SASO), which sets and enforces the technical regulations for pipe used in the Kingdom. Products are registered through SASO's conformity route and evidenced with a certificate of conformity. You can review the regulator's official remit on saso.gov.sa. Always confirm the SAS class your consultant specifies and request the matching certificate of conformity from the manufacturer.
How to Choose the Right Sewer Pipe Size & Class
Two decisions dominate a drainage specification: diameter (driven by peak flow and self-cleansing velocity) and class (driven by burial depth and loading). As a practical guide for Saudi projects:
- Building & residential drainage: 110–160 mm solid-wall uPVC, Class 2–3, for house connections and internal site drainage.
- Residential subdivision / compound networks: 200–315 mm, Class 3, for collector sewers.
- Municipal & trunk sewers: 400–710 mm, Class 3–4, for main gravity sewers under roads and heavy loading.
- Stormwater mains: up to 710 mm, sized to the design storm return period.
- Sub-soil dewatering: 75–500 mm perforated uPVC, slot pattern matched to soil and water table.
Fittings, Bends & Junctions for Drainage Runs
A gravity sewer is only as reliable as its junctions. Every change of direction, branch connection, and inspection point needs a fitting that matches the pipe's class and keeps the joint watertight. 4B Factory supplies matching uPVC bends, junctions, reducers, couplings, and fabricated specials rated to the sewer line's specification, so a Class 4 trunk sewer isn't compromised by an under-rated bend. For long-radius sweeps, saddle connections, and non-standard geometry, fabricated drainage products are made to the project's exact requirement rather than forced from stock parts.
Sewage & Drainage Applications Across Saudi Arabia
uPVC sewer and drainage pipe from 4B Factory serves the full range of Saudi drainage projects, delivered factory-direct from the Al-Kharj plant:
- Municipal sewerage networks — city foul and storm sewers for local authorities and contractors.
- Residential compounds & subdivisions — collector and connection drainage for housing schemes.
- Road & highway drainage — culverts and storm drains for infrastructure projects.
- Industrial estates — effluent and wastewater drainage for plants and factories.
- Agricultural land drainage — perforated pipe for sub-soil dewatering and salinity control across farming regions like Al-Kharj.
Delivery Across the Kingdom — Factory-Direct From Al-Kharj
4B Factory manufactures sewage and drainage pipe at its plant in Al-Kharj Industrial District 27 and delivers factory-direct to Riyadh and the central region, the Eastern Province (Dammam, Khobar, Dhahran, Jubail), and the Western region (Jeddah, Makkah, Madinah). Because supply comes straight from the manufacturer with no distributor margin, project pricing stays competitive and lead times stay short for bulk and project-scale orders. Standards documentation and certificates of conformity are supplied with every order for municipal and contractor approval.
Frequently Asked Questions
uPVC sewer and drainage pipe is the standard for wastewater and stormwater networks in Saudi Arabia. Manufactured to SAS 1395/1396 in Classes 2–4 and diameters 110–710 mm, it is corrosion-free, watertight, and used for gravity foul sewers, storm drainage, and culverts across the Kingdom.
uPVC sewer and drain pipe in Saudi Arabia is manufactured to Saudi Standards SAS 1395 and SAS 1396, aligned with SASO ISO 4435 for SDR sewer pipe. These standards define the material, dimensions, ring-stiffness classes, and test requirements for underground drainage pipe.
Solid-wall sewer pipe carries wastewater and stormwater in a sealed, watertight system. Perforated drainage pipe has slots or holes in the wall that let groundwater seep in, so it is used for sub-soil dewatering and land drainage — lowering the water table — not for carrying sewage.
Size the pipe to the peak flow: 110–160 mm for building drainage, 200–315 mm for residential subdivision collectors, and 400–710 mm for municipal trunk and storm sewers. A drainage engineer confirms the hydraulic sizing and self-cleansing gradient for the specific network.
uPVC sewer pipe comes in Class 2–4 to SAS 1395/1396, graded by ring stiffness. Use Class 2–3 for shallow residential runs and Class 3–4 for deeper municipal mains and any pipe under trafficked roads, where soil and surcharge loading is highest.
For most Saudi drainage applications, yes. uPVC resists the hydrogen-sulphide corrosion that attacks concrete sewers, keeps a smoother self-cleansing bore, weighs far less for faster installation, and seals watertight at the joints. Concrete still suits very large culverts, but uPVC dominates 110–710 mm gravity drainage.
4B Factory manufactures uPVC sewer and drainage pipe in Al-Kharj, about an hour from Riyadh, and delivers factory-direct across the Kingdom. Sizes run 110–710 mm in Classes 2–4 to SAS 1395/1396, with standards documentation supplied for project approval.
Specifying a Sewage or Drainage Project?
Send your pipe diameter, SAS class, quantities and delivery location for a factory-direct quotation with standards documentation.