Pakistan allegedly produces heavy water at the Khushab complex, near the Khushab-1 and Khushab-2 plutonium production reactors. The facility reportedly commenced operations in April 1998, [2] and has an estimated production capacity of between 50 and 100 tons of heavy water per year. [3] Before operations began, China allegedly oversupplied Pakistan with heavy water for the Karachi Nuclear Power Plant (KANUPP), which Pakistan then diverted to Khushab-1. [4] Like Khushab-1 and Khushab-2, this facility is not under IAEA safeguards.

Sources:
[1] David Albright and Paul Brannan, "Pakistan Appears to be Building a Fourth Military Reactor at the Khushab Nuclear Site," Institute for Science and International Security, 9 February 2011, www.isis-online.org.
[2] Nuclear Black Markets: Pakistan, A.Q. Khan and the Rise of Proliferation Networks (International Institute for Strategic Studies: London, 2007).
[3] Simon Beck, "Chinese heavy water linked to military plutonium-processing plant," South China Morning Post (Hong Kong), 16 May 1998, www.lexisnexis.com.
[4] "Analysis of IKONOS Imagery of the Newly-Identified Heavy Water Plant at Khushab, Pakistan," Institute for Science and International Security, 16 March 2000, www.isis-online.org.