PFAS substances in firefighting foams have also been found in water around the Ohakea Air Force Base, but the direction of water flow would not take them to the Bulls water supply.
The New Zealand Defence Force (NZDF) is to pay specialists to test groundwater in existing wells near Kakariki, a spokesperson said.
The results will be provided to the landowners, local councils and to the Government group responding to instances of PFAS contamination.
The testing will determine whether a one-off event like using foam in the crash could be affecting groundwater 20 years later.
In spring the NZDF will also undertake a fourth round of testing for PFAS compounds around Ohakea.
The poly-fluoroalkyl (PFAS) substances are toxic and long-lasting in the environment.
They are found in firefighting foams and other products. The NZDF says the foams it uses have contained only trace amounts since 2002.