v3.26.1
Cover
12 Months Ended
Dec. 30, 2025
Document Information [Line Items]  
Document Type 11-K
Entity Registrant Name American States Water Company
Amendment Flag false
Entity Central Index Key 0001056903
EBP 005  
Document Information [Line Items]  
Document Type 11-K
Entity Registrant Name American States Water Company
Amendment Flag false
Entity Central Index Key 0001056903