Saprol 190 EC (triforine) and Rubigan 12 EC (fenarimol) diluted in 6 types of water were applied against rose rust Phragmidium mucronatum Cooke. No adjuvants were added to the emulsion except when the spray mix was made using water from Poznań prepared in 2 variants: with an addition of Citowett AL and without it. Independently on the plant protection product type, efficacy of fungicides diluted in well water from Szczepankowo, Kościan or Śmigiel was better than when they were diluted in water after reversed osmosis. However, no type of water exerted any significant effect on efficacy of the investigated fungicides independently on the year of studies, although, in 1999, a better biological activity was shown by Rubigan 12 EC diluted in water from Kościan and Poznań than when they were diluted in water after reversed osmosis. The fungicides were most effective after addition of Citowett AL, however, a visible effect of this adjuvant showing increased rose protection against rose rust was found only in 1998