diff --git a/packages/grafana-alerting/src/grafana/rules/components/state/types.ts b/packages/grafana-alerting/src/grafana/rules/components/state/types.ts
index c37ff0851f4..65e2c165f2f 100644
--- a/packages/grafana-alerting/src/grafana/rules/components/state/types.ts
+++ b/packages/grafana-alerting/src/grafana/rules/components/state/types.ts
@@ -1,3 +1,3 @@
-export type Health = 'nodata' | 'error';
+export type Health = 'ok' | 'nodata' | 'error';
 export type State = 'normal' | 'firing' | 'pending' | 'unknown' | 'recovering';
 export type Type = 'alerting' | 'recording';
diff --git a/public/app/features/alerting/unified/rule-list/components/util.ts b/public/app/features/alerting/unified/rule-list/components/util.ts
index c04ad5b3f0b..60e5f6d5352 100644
--- a/public/app/features/alerting/unified/rule-list/components/util.ts
+++ b/public/app/features/alerting/unified/rule-list/components/util.ts
@@ -93,7 +93,7 @@ export function normalizeHealth(health?: RuleHealth): NormalizedHealth {
 }
 
 function isValidHealth(health: string): health is NonNullable<NormalizedHealth> {
-  const valid: Array<NonNullable<NormalizedHealth>> = ['nodata', 'error'] as const;
+  const valid: Array<NonNullable<NormalizedHealth>> = ['ok', 'nodata', 'error'] as const;
   return valid.some((v) => v === health);
 }
 
diff --git a/public/app/features/alerting/unified/rule-list/hooks/filters.test.ts b/public/app/features/alerting/unified/rule-list/hooks/filters.test.ts
index 18e4af4f40f..729576da9f2 100644
--- a/public/app/features/alerting/unified/rule-list/hooks/filters.test.ts
+++ b/public/app/features/alerting/unified/rule-list/hooks/filters.test.ts
@@ -138,9 +138,26 @@ describe('ruleFilter', () => {
       health: RuleHealth.Error,
     });
 
+    const prometheusErrorRule = mockPromAlertingRule({
+      name: 'Error Rule',
+      health: 'err',
+    });
+
     expect(ruleFilter(healthyRule, getFilter({ ruleHealth: RuleHealth.Ok }))).toBe(true);
     expect(ruleFilter(healthyRule, getFilter({ ruleHealth: RuleHealth.Error }))).toBe(false);
     expect(ruleFilter(errorRule, getFilter({ ruleHealth: RuleHealth.Error }))).toBe(true);
+    expect(ruleFilter(prometheusErrorRule, getFilter({ ruleHealth: RuleHealth.Error }))).toBe(true);
+  });
+
+  it('should normalize health values when filtering', () => {
+    // Legacy Prometheus health value 'err' should be normalized to 'error'
+    const legacyErrorRule = mockPromAlertingRule({
+      name: 'Legacy Error Rule',
+      health: 'err',
+    });
+
+    // When filtering for 'error', it should match rules with health 'err' (legacy) or 'error'
+    expect(ruleFilter(legacyErrorRule, getFilter({ ruleHealth: RuleHealth.Error }))).toBe(true);
   });
 
   it('should filter by dashboard UID', () => {
diff --git a/public/app/features/alerting/unified/rule-list/hooks/filters.ts b/public/app/features/alerting/unified/rule-list/hooks/filters.ts
index 2e9535dd97f..96db43ad35a 100644
--- a/public/app/features/alerting/unified/rule-list/hooks/filters.ts
+++ b/public/app/features/alerting/unified/rule-list/hooks/filters.ts
@@ -11,6 +11,7 @@ import { getDatasourceAPIUid } from '../../utils/datasource';
 import { fuzzyMatches } from '../../utils/fuzzySearch';
 import { parseMatcher } from '../../utils/matchers';
 import { isPluginProvidedRule, prometheusRuleType } from '../../utils/rules';
+import { normalizeHealth } from '../components/util';
 
 /**
  * @returns True if the group matches the filter, false otherwise. Keeps rules intact
@@ -79,7 +80,7 @@ export function ruleFilter(rule: PromRuleDTO, filterState: RulesFilter) {
     }
   }
 
-  if (filterState.ruleHealth && health !== filterState.ruleHealth) {
+  if (filterState.ruleHealth && normalizeHealth(health) !== filterState.ruleHealth) {
     return false;
   }