Guide To Liquid Cooling Decommissioning And Retirement

Most GPU decommissioning playbooks were written for gear you unplug and roll out. What happens when they’re high-density D2C racks?

A liquid-cooled rack adds a drain sequence, a fluid you must identify before you can legally dispose of it, and paperwork that belongs next to your certificates of destruction. Miss any of it in planning and you pay on site in schedule slips, spills, or a compliance gap you didn’t know you had.

Fast Facts: What You Need To Know About Decommissioning Liquid Cooled IT Gear

• Liquid cooling covers about 53% of AI chips in 2026, up from roughly 33% in 2025.
• The cooling loop must be isolated and drained before de-racking starts, and OCP guidance uses compressed dry air below 75 psi to push residual fluid under 5%.
• Most direct-to-chip loops run PG25 (75% water, 25% propylene glycol), which is PFAS-free. 
• Immersion systems use dielectric fluids that can contain PFAS and follow a different disposal path.
• Drain logs, waste determinations, and disposal manifests belong in the same chain-of-custody file as your data destruction records.
• A GPU from a properly drained and dried loop is valued like any other retired GPU, while a half-drained unit invites corrosion.
  

AI Power Capacity Demand Liquid Cooling

TrendForce projects liquid cooling penetration among AI chips will climb from about 33% in 2025 to 53% in 2026. Google already runs liquid cooling in more than 80% of its AI servers. Across the broader market, a November 2025 S&P Global 451 Research survey found only 45% of data centers still run purely on air cooling, with 59% planning to add some liquid cooling within five years.

Heat density forced the change. The GB200 NVL72 pulls 120-130 kW per rack, while air cooling was built around 8-12 kW racks, according to Network World. 

Those figures track what’s going into data halls. OCP reference guidance notes that IT equipment refreshes every 3-5 years are common, which puts the first big wave of liquid-cooled racks on decommission schedules right now. 

Decommissioning A Liquid-Cooled GPU Rack Starts With Plumbing

On an air-cooled rack, removal starts once power is off and cables are labeled. On a liquid-cooled rack, removal waits on the technology cooling system (TCS), which is the loop running from the coolant distribution unit (CDU) through the rack manifold to every cold plate. Technicians need to isolate that system from facility water and drain it.

The steps to perform a drain procedure are well documented. The Open Compute Project’s March 2026 guidance on shipping and storing cold plate hardware, written by engineers from Meta and NVIDIA, describes purging assemblies with compressed clean dry air below 75 psi for several minutes to bring residual fluid under 5%. It defines “dry” hardware as under 10% coolant by volume and says to release purge pressure before transport.

Weight is the second change. A fully loaded GB200 NVL72 rack at about 3,245 pounds, per HPE’s spec sheet, calls for rated lift equipment and a floor-loading check along the entire exit path, from the rack position to the dock.

Operators close and tag the valves on the facility side, then the rack side gets drained and purged. Only then does anyone break a connection or pull a tray. In a colocation hall, the CDU and facility water often belong to the provider while the manifolds and cold plates belong to you.

Your Disposal Path Depends On Which Fluid You’re Using

Single-phase direct-to-chip cooling holds about 55% of the liquid cooling market in 2026, according to Schneider Electric, and it typically runs PG25. At a 25% concentration, propylene glycol makes the mix biostatic, which keeps algae and bacteria off cold plate fins spaced around 50 microns apart. It is also far less toxic than ethylene glycol, which is why OCP recommends it.

Immersion systems come with different considerations. Immersion tanks use dielectric fluids, and two-phase systems have historically relied on fluorocarbon fluids containing PFAS, including 3M’s Novec line, which 3M has stopped producing. EPA’s PFAS reporting deadline under TSCA now sits at January 31, 2027, and New Jersey, Maine, Massachusetts, Minnesota, and Washington have or are planning their own reporting requirements.

Identify the fluid from the safety data sheet and system documentation before the drain date. PG25 from a cold plate loop and a fluorocarbon from a two-phase tank leave your building on completely different paperwork. 

GPU Rack Coolant Disposal Needs Its Own Chain of Custody

Quick-disconnect fittings still leak a little. Schneider’s thermal engineers note that QDs often give a slightly wetted disconnect instead of a fully dry break, which is part of why the industry settled on low-toxicity PG25. Across a row of racks those drops add up, so keep drip trays, absorbent pads, and leak detection active until the last hose comes off.

Used coolant is not automatically hazardous waste. The EPA’s position is that glycol coolant isn’t a listed hazardous waste, so it only has to be managed as one if it shows a hazardous characteristic, typically confirmed with a Toxicity Characteristic Leaching Procedure (TCLP) test. Whoever drains it has to make and document that determination, states can regulate it more strictly, and dumping it down a floor drain is off the table (Connecticut, for one, bars antifreeze discharge to sanitary sewers without state authorization).

Coolant isn’t one of the focus materials under R2v3, which cover items such as circuit boards, batteries, and mercury. The specific rules come from RCRA and your state environmental agency, so a vendor’s R2v3 certificate alone doesn’t prove they can handle PG25 coolant disposal.

Your audit file needs the same rigor you already demand for drives, with the following info:

• A drain log per rack with:
  • Date 
  • Volume 
  • Techniker 
• The waste determination 
• The hauler’s manifest or recycling receipt 
• Photos of tagged-out isolation valves.
  

Plan Your Cooling Exit Strategy In Advance

Drain-and-cap work belongs in the project plan on day one, next to asset inventory and data sanitization, because it controls crew skills, lift rentals, freight mode, and the order racks leave the floor. A full decommissioning project plan should name who isolates facility water, who drains the rack side, which fluid sits in each loop, and where every drum goes.

Freight requires its own line item. OCP’s guidance puts standard road freight between -20°C and 45°C, and PG25 enters a slush zone between -10°C and -15°C. 

Liquid cooling changes how the hardware comes out of the rack. A retired GPU’s value still comes down to model, condition, test results, and what the secondary market is paying at the time.

The one place a coolant loop can still cost you money is the warehouse. OCP flags hardware left partially drained as a high corrosion risk that isn’t suited to long-term storage, while fully dried assemblies charged with nitrogen at 25 to 50 psi typically hold for 3 to 12 months. Once your trays are dry and documented, see what your retired GPUs are worth.