Rotom Wash's Weaknesses

Best Counters

The type that is strong against Rotom Wash is Grass type Pokemon.

For the best defense, Grass and Dragon types have very effective defense against Rotom Wash, and will be resistant to damage from Rotom Wash's STAB attacks:

Ground types will also deal super-effective damage against Rotom Wash, but be careful using Pokemon of this type because they may also receive extra damage from some of Rotom Wash's attacks!

Weaknesses

Rotom Wash's type is Electric and Water.

Rotom Wash has a weakness to Grass and Ground types. These Pokemon types will be strong against Rotom Wash, causing Rotom Wash to take a super effective double (2x) damage from attacks of those types.

Please keep in mind that Rotom Wash is resistant to attacks from Fire, Flying, Ice, Water, Steel types, and these attacks are not very effective and cause reduced damage, so they should be avoided.