Analysis
SEPCOIII reports that Rabigh 4 completed its EPC performance test at 600,000 m3/day on 19 February 2026, with power use of 2.712 kWh/m3 before photovoltaic offset. SWPC has not published commercial-operation acceptance, and the marine close-out file remains unavailable.
SEPCOIII says Rabigh 4 completed its performance test on 19 February 2026 at the plant's 600,000 m3/day design capacity. The contractor reported specific power use of 2.712 kWh/m3, or 2.659 kWh/m3 after photovoltaic generation. The notice fixes the date, output and energy basis of an integrated EPC test.
Saudi Water Partnership Company is the offtaker whose acceptance governs the water-purchase term. No SWPC commercial-operation certificate or equivalent owner notice is public, so Rabigh 4 remains in commissioning for now.
Milestone authority and scope
A contractor test, owner certificate, as-built marine record and operating series establish different parts of the plant's technical and commercial status.
The EPC contractor, developer, owner, offtaker, regulator, lender and independent evaluator each have authority over different technical or commercial decisions.
The issuing party defines which milestone the evidence can establish.Tested block, duration, output, water quality, energy basis, operating mode and included shared systems define the performance claim.
The result applies only to the equipment, duty and period covered by the test.Final surveys, alignments, levels, structures, joints, pressure or leak tests, intake availability, outfall hydraulics and diffuser condition describe the permanent sea connection.
As-built and integrity records establish the delivered marine asset.Treatment trains, intake, outfall, power, storage, transfer and control systems must operate together at the accepted duty.
Shared assets and downstream interfaces support the declared plant capacity.Provisional acceptance, completion certificates, commercial-operation certificates and operating releases record the accountable party's decision and any unresolved conditions.
Contract acceptance establishes the commercial milestone.Repeat output, availability, downtime, intake condition, discharge quality, plume behaviour, maintenance and measured user outcomes describe performance after handover.
Operating and environmental series extend a single test into a service record.Five public milestones
A test, first water, block commissioning, commercial operation and completed civil works each close a different part of the delivery chain.
Modern Marine's project record gives the seawater system a 1,500,000 m3/day intake and a 900,000 m3/day outfall. Both flows exceed product-water output because the process draws feedwater and returns a concentrated stream. Running the plant at full output required that system, but SEPCOIII's notice publishes no marine close-out detail.
Final alignment and levels, intake-screen and pump availability, pipe integrity, diffuser condition, outfall hydraulics, as-built surveys and environmental acceptance are still absent from the public file. Storage availability, punch-list closure and long-run receiving-water performance also sit outside the reported power-use result.
DEWA has placed Hassyan Block A, the first 60 MIGD, in its installed-capacity record. Another 120 MIGD remains in delivery. Full-phase acceptance will cover the remaining blocks together with the shared intake, outfall and diffuser system.
SADDN reached a different point when desalinated water arrived at Codelco's Radomiro Tomic reservoir. Water had crossed the Pacific intake, treatment plant, pumping stations and more than 160 km of high-head conveyance. Techint described progressive commissioning and interface validation, with accepted 840 l/s service and the BOOT operating term still ahead.
ACWA's current Taweelah RO profile supplies the later-stage statement missing at Rabigh 4: commercial operations from Q1 2024. That supports an operating classification for the 200 MIGD plant. Earlier ACWA reporting also recorded phased production and a Group 2 commercial-operation certificate before the current full-project status.
The public marine file still ends at proposed intake and outfall layouts and bid-stage flow assumptions in the environmental appendices. A repair tender would need final route, depth, joint, diffuser and condition data before contractors could price work on the sea connection.
South Tarawa provides the long view. ADB records its three ocean-outfall civil package complete in August 2018, testing and commissioning in the second quarter of 2019, and whole-project physical completion at the end of that year.
ADB's later completion and independent evaluation reports found mixed water-quality and service outcomes after the outfalls were built. Operating capability then depended on maintenance, staffing, monitoring, network connections and repeated performance after handover.
The World Bank's desalination guidance describes the water purchase agreement as the contract that fixes delivered quantity, quality, pressure and tariff, while some operating performance becomes verifiable only after commissioning. Its PPP risk-allocation guidance similarly places minimum output, quality, efficiency and environmental tests before permission to enter commercial operation.
Rabigh 4 therefore has a reported full-capacity EPC test with a stated energy-performance result. No public owner or offtaker acceptance record has followed. Its public classification remains commissioning until SWPC or another contractually accountable party confirms commercial operation; final marine geometry, hydraulic acceptance and receiving-water compliance also remain unpublished.
Subject index
These subject pages bring together related projects, technical articles, reports, and evidence methods.
Full-capacity test date, output, power-use figures and article image.
Project-specific intake and outfall design flow rates and marine role.
Plant capacity, storage, project structure, 25-year water purchase agreement and scheduled commissioning.
BOOT and water-purchase-agreement boundaries for delivered quantity, quality and pressure, including the distinction between commissioning tests and operating performance.
Commissioned 60 MIGD block and remaining 120 MIGD delivery boundary.
Project-specific intake, outfall, diffuser and future-expansion marine design context.
First-water event, connected route and progressive commissioning boundary.
Developer, owner and operating responsibilities across commissioning and service.
Current 200 MIGD capacity and commercial-operations date.
Proposed marine layouts and model flow assumptions, not final as-built geometry.
Civil completion, testing and commissioning sequence plus mixed water-quality and service outcomes.
Independent post-completion assessment of outcome and sustainability limits.