What is the ruling on liquid that splashed me from the water used to irrigate newly planted crops, given that it has a foul odor, and someone informed me that it is sewage water, and I also saw a worker bathing and performing ablution with it?

The basic principle concerning water is that it is pure. Therefore, whoever doubts the impurity of water should consider it pure, because certainty is not removed by doubt. The claim of the water's impurity is contradicted by the act of someone performing ablution with it, and he is more knowledgeable of its state since he uses it to irrigate plants. The suspicious odor does not affect the ruling, for the water is pure unless there is evidence to prove its impurity.