Water Heater Repair on Partial Rental Property / Primary Residence

My water heater broke in 2022 and I paid someone to fix it. This is for my primary residence in which I rent out 2 out of the 5 bedrooms. Can I deduct the repair cost against the rental income for 2022. Would I prorate it based on the rental percentage I use for other expenses or is the full amount deductible. 

The repair was not an improvement as the existing unit was reused and a new control was added to it so it would start again.
The amount was $600 even for the repair.
The two bedrooms were rented the full year and are ~12% of the total house sqft. Would the deduction be 600*.12?