Justices of the peace are judges who handle both civil and criminal cases, including small claims court, justice court, and administrative hearings. In practical terms, these are lawsuits over debts, evictions, car accidents, unlawful towing, and property.

Their criminal workload involves disposing of all class C criminal misdemeanor complaints, such as traffic citations, issuance of bad check, and others. These cases involve payment, setting contested cases for trial, and pretrial hearings with the county prosecutor.

Other duties include presiding over peace bond hearings, reviewing applications for mental health or chemically dependent commitments, conducting compulsory school attendance trials, and giving warnings to juveniles required by law. They issue warrants for and conduct hearings concerning seizure and disposition of cruelly treated animals. Most justices of the peace perform marriage ceremonies as well.

In Washington State, justices of the peace are not a common feature of the modern legal system as they are in some other jurisdictions. Instead, Washington has district courts that handle many of the functions traditionally associated with justices of the peace. District court judges in Washington preside over civil cases, including small claims matters, contract disputes, and landlord-tenant issues such as evictions. They also handle criminal misdemeanors and gross misdemeanors, traffic infractions, anti-harassment orders, and some administrative hearings. District courts do not typically handle class C felonies, which are generally the purview of superior courts. Additionally, district court judges may issue search and arrest warrants, preside over preliminary hearings, and conduct trials for criminal offenses that fall within their jurisdiction. They may also perform marriage ceremonies. For mental health or chemical dependency commitments, the proceedings are usually handled by superior courts or designated mental health professionals, depending on the circumstances. It's important to note that the specific duties and titles of judicial officers can vary by county within the state.