diff --git a/water-api/src/controllers/concentrator.controller.ts b/water-api/src/controllers/concentrator.controller.ts
index 01fe205..6afa522 100644
--- a/water-api/src/controllers/concentrator.controller.ts
+++ b/water-api/src/controllers/concentrator.controller.ts
@@ -1,4 +1,4 @@
-import { Response } from 'express';
+import { Request, Response } from 'express';
 import { AuthenticatedRequest } from '../types';
 import * as concentratorService from '../services/concentrator.service';
 import { CreateConcentratorInput, UpdateConcentratorInput } from '../validators/concentrator.validator';
diff --git a/water-api/src/services/concentrator.service.ts b/water-api/src/services/concentrator.service.ts
index dc77914..b601003 100644
--- a/water-api/src/services/concentrator.service.ts
+++ b/water-api/src/services/concentrator.service.ts
@@ -6,6 +6,8 @@ import { CreateConcentratorInput, UpdateConcentratorInput } from '../validators/
  */
 export type ConcentratorType = 'LORA' | 'LORAWAN' | 'GRANDES';
 
+export type ConcentratorStatus = 'ACTIVE' | 'INACTIVE' | 'MAINTENANCE' | 'OFFLINE';
+
 /**
  * Concentrator entity interface
  */
@@ -16,7 +18,7 @@ export interface Concentrator {
   project_id: string;
   location: string | null;
   type: ConcentratorType;
-  status: 'online' | 'offline' | 'maintenance' | 'unknown';
+  status: ConcentratorStatus;
   ip_address: string | null;
   firmware_version: string | null;
   created_at: Date;