Steel Pipe for Desalinated Water Transmission: Lining Selection for Product Water Pipelines

For desalinated water transmission, choose the internal lining using the water that will actually enter the pipeline after the specified post-treatment and blending. Then select the steel pipe body, external protection and joints against the approved route and design conditions. Low salt content is not enough information to approve an unlined pipe or any particular lining.

The scope here is product-water transfer from a desalination plant toward pumping stations, reservoirs and distribution supply. Seawater intake, reverse-osmosis process piping and brine outfall are separate services. Do not carry a material choice from one of those duties into the finished-water transmission order.

For raw water, reclaimed water or another conveyed medium, start with the Steel water pipe selection by service to identify the matching service guide and required inputs.

Conceptual desalination and product-water transfer scene. The landward pipeline is the subject of this guide; the illustration is not a real project reference.

Desalinated Water Pipelines: Where Product Water Transmission Fits

Middle East project relevance is visible in SWPC’s separate desalinated-water transmission programme. That supports treating the external main as its own buying task; it does not establish a required lining or steel grade. SWPC Company Profile 2026.

Why Final Water Chemistry Decides the Lining for Desalinated Water

Reverse-osmosis permeate is very low in dissolved minerals, so it has little hardness or alkalinity and can be aggressive to unprotected metal and to cement-based materials. For that reason product water is normally post-treated, typically by adding calcium and alkalinity and adjusting pH, and sometimes blended with other sources, before it is supplied. WHO’s desalination guidance places post-treatment and distribution within the water-safety assessment, and Ofwat explains that desalinated seawater is remineralised before drinking-water supply. These references support reviewing the final water rather than selecting pipe from the word “desalinated”. Neither provides a universal lining recipe. WHO Safe Drinking Water from Desalination; Ofwat Desalination Explained.

Langelier Saturation Index and CCPP: what to ask for

If the design team uses the Langelier Saturation Index (LSI), calcium carbonate precipitation potential (CCPP) or another stability index, request its assumptions, calculation conditions and acceptance basis. A single index value does not replace the full water analysis, lining-product evidence or assessment of all corrosion mechanisms. The purchaser should transmit the approved assessment rather than invent a pass/fail threshold.

Where the final accepted use is drinking water, also check potable-water lining and joint-material approval; a water-chemistry assessment and drinking-water health-effects acceptance address different questions.

Product water is assessed after the specified treatment and blending. Data for raw seawater or an intermediate process stream is not a substitute.

Cement Mortar vs Epoxy vs FBE Lining for Desalinated Water Pipelines

Compare lining systems only within the approved specification and the offered product's limits. The AWWA families in play are cement mortar (C205), liquid epoxy (C210), FBE (C213) and polyurethane (C222). Steel Mains discusses water chemistry and low-flow residence conditions in its mortar-lining guidance. Use that as a reason to request a project review, not as a prediction that every mortar-lined desalinated-water main will fail. Steel Mains Introduction to Cement Mortar Lining.

Commissioning a new mortar-lined main

Fresh cement mortar can raise pH and alkalinity in water standing in the line, most noticeably in low-flow or stagnant conditions. Agree flushing, filling and early water-quality monitoring with the owner before the line is commissioned, and keep the lining supplier’s curing and handling instructions in the purchase documents.

Steel Pipe Body for Desalination Transmission Lines: SSAW, LSAW and ERW

For the bulk main, evaluate SSAW pipe or LSAW pipe against the approved size, grade, wall, manufacturing route, external loads and inspection. Review ERW pipe for connection lines where the product envelope and specification permit. “Desalinated” does not establish a pipe-body grade, and the route choice follows the design, not the water source. Verify fittings, valve interfaces and the internal joint repair before accepting a shop-only lining quotation.

External Coating and Corrosion Protection for Coastal and Saline-Ground Routes

Desalination plants sit on the coast, so transmission routes often cross saline groundwater, chloride-bearing soil and, on Gulf routes, sabkha ground. The inside of the pipe and the outside face different environments and need separate specifications. Assess buried and exposed sections separately: buried sections can combine a polymer coating with a cathodic protection design where the project specifies it, while exposed sections near the plant need an atmospheric coating suited to salt-laden air and sun. If liquid epoxy lined pipe or FBE pipe is proposed, keep the internal and external specifications distinct.

Desalination Pipeline Materials by Duty: Intake, RO, Product Water and Brine

No single material suits every duty in a desalination scheme. Use the table to see which duties this guide covers, not to rank materials.

The procurement handoff links the final water specification to lining approval and the pipe schedule to fabrication. Both must meet at the joint review.

Common Desalinated Water Pipeline Mistakes

Desalinated Water Steel Pipe RFQ Checklist

Supply the information below, and identify which data is approved and which remains open. Request confirmation of the exact lining system and scope before treating a commercial offer as technically complete.

Use the AWWA standards map to locate the appropriate product and protection references, and the water-pipe field joint guide to close installation interfaces. These details matter more than adding “desalination grade” to a generic pipe description.

FAQ: Steel Pipe for Desalinated Water

Can cement mortar lined steel carry desalinated water?

It is a candidate only after the project confirms compatibility with the actual post-treated water, lining system and operating conditions. The source-water label alone cannot approve or reject it.

Is stainless steel required for every desalination pipe?

No single material applies to all plant and transmission duties. Locate the pipe in the process, define its exposure and obtain the approved material selection.

Why is desalinated water aggressive to pipes?

Reverse-osmosis permeate has little hardness or alkalinity. Post-treatment and blending adjust this, which is why the final water, not the raw seawater, governs the lining review.

Should a supplier choose the remineralisation target?

The treatment and design team establishes the water specification. The pipe supplier should assess the offered product against that approved basis rather than set treatment targets.

Is desalinated water the same as potable water in a pipe order?

Not automatically. Desalinated describes a treatment route; potable describes an accepted end use. Record both so the supplier knows what will contact the pipe.

Related Articles

Steel water pipe selection by service

Potable water transmission guide

Steel pipe for sewage force mains guide

Slurry pipeline steel pipe and lining guide

AWWA steel water pipe standards map

FBE water pipe procurement

Field joints for steel water pipe

References and Sources

WHO Safe Drinking Water from Desalination

Ofwat Desalination Explained

Steel Mains Introduction to Cement Mortar Lining

SWPC Company Profile 2026