diff --git a/apps/as/src/entities/instl-sncn/index.ts b/apps/as/src/entities/instl-sncn/index.ts
index 8fdbb442f..a1959a277 100644
--- a/apps/as/src/entities/instl-sncn/index.ts
+++ b/apps/as/src/entities/instl-sncn/index.ts
@@ -1,6 +1,7 @@
 export { InstlSncnApi } from "./api/instl-sncn-service";
-export type {
-  InstlSncnMng,
-  InstlSncnMngSearchParams,
-  SpringPage,
+export {
+  INSTL_SNCN_REGISTER_SELECTION_KEY,
+  type InstlSncnMng,
+  type InstlSncnMngSearchParams,
+  type SpringPage,
 } from "./model/instl-sncn-interface";
diff --git a/apps/as/src/entities/instl-sncn/model/instl-sncn-interface.ts b/apps/as/src/entities/instl-sncn/model/instl-sncn-interface.ts
index 00a51b76b..d0c19aa35 100644
--- a/apps/as/src/entities/instl-sncn/model/instl-sncn-interface.ts
+++ b/apps/as/src/entities/instl-sncn/model/instl-sncn-interface.ts
@@ -1,3 +1,5 @@
+export const INSTL_SNCN_REGISTER_SELECTION_KEY = "instlSncnRegisterSelection";
+
 export interface SpringPage<T> {
   content: T[];
   totalElements: number;
diff --git a/apps/as/src/pages/instl-sncn/ui/cnfm-list-page.tsx b/apps/as/src/pages/instl-sncn/ui/cnfm-list-page.tsx
index 0b126f54c..a5ff158dd 100644
--- a/apps/as/src/pages/instl-sncn/ui/cnfm-list-page.tsx
+++ b/apps/as/src/pages/instl-sncn/ui/cnfm-list-page.tsx
@@ -7,7 +7,11 @@ import { useQuery } from "@tanstack/react-query";
 
 import { dayjs } from "@/shared/lib";
 import { useCodeList } from "@/entities/code";
-import { InstlSncnApi, type InstlSncnMngSearchParams } from "@/entities/instl-sncn";
+import {
+  INSTL_SNCN_REGISTER_SELECTION_KEY,
+  InstlSncnApi,
+  type InstlSncnMngSearchParams,
+} from "@/entities/instl-sncn";
 
 import "./cnfm-page.css";
 
@@ -69,7 +73,7 @@ function CnfmListPage() {
   const [taskDialogOpen, setTaskDialogOpen] = useState(false);
   const [selectedTaskSeComCd, setSelectedTaskSeComCd] = useState("");
 
-  const { data: fnrsCodeList = [] } = useCodeList("FNRS");
+  const { data: fnrsCodeList = [] } = useCodeList("INSTL");
 
   useEffect(() => {
     if (!taskDialogOpen) return;
@@ -112,12 +116,15 @@ function CnfmListPage() {
     const selected = fnrsCodeList.find((item) => item.lwpoCd === selectedTaskSeComCd);
     if (!selected) return;
 
-    const query = new URLSearchParams({
-      taskSeComCd: selected.lwpoCd,
-      taskSeComCdNm: selected.lwpoCdNm,
-    });
+    sessionStorage.setItem(
+      INSTL_SNCN_REGISTER_SELECTION_KEY,
+      JSON.stringify({
+        taskSeComCd: selected.lwpoCd,
+        taskSeComCdNm: selected.lwpoCdNm,
+      }),
+    );
     setTaskDialogOpen(false);
-    router.push(`/instl-sncn/register?${query.toString()}`);
+    router.push("/instl-sncn/register");
   };
 
   return (
diff --git a/apps/as/src/pages/instl-sncn/ui/cnfm-regist-page.tsx b/apps/as/src/pages/instl-sncn/ui/cnfm-regist-page.tsx
index 9fbd1f552..760b410df 100644
--- a/apps/as/src/pages/instl-sncn/ui/cnfm-regist-page.tsx
+++ b/apps/as/src/pages/instl-sncn/ui/cnfm-regist-page.tsx
@@ -1,12 +1,13 @@
 "use client";
 
 import { useEffect, useMemo, useState } from "react";
-import { useRouter, useSearchParams } from "next/navigation";
+import { useRouter } from "next/navigation";
 
 import { useQuery } from "@tanstack/react-query";
 
 import type { AcntgSeMngTreeDto } from "@/entities/acntg";
 import { acntgService } from "@/entities/acntg";
+import { INSTL_SNCN_REGISTER_SELECTION_KEY } from "@/entities/instl-sncn";
 import { Button, Input } from "@common/components";
 
 import "./cnfm-page.css";
@@ -55,14 +56,23 @@ const ReadCell = ({ value }: { value: string | number }) => (
 /* ------------------------------------------------------------------ */
 function CnfmRegistPage() {
   const router = useRouter();
-  const searchParams = useSearchParams();
-
-  const taskSeComCdNm = searchParams?.get("taskSeComCdNm") || "하수관로";
-  const [taskSeComCd, setTaskSeComCd] = useState("");
+  const [taskSeComCdNm, setTaskSeComCdNm] = useState("재이용수");
+  const [taskSeComCd, setTaskSeComCd] = useState("RE");
 
   useEffect(() => {
-    setTaskSeComCd(searchParams?.get("taskSeComCd") || "");
-  }, [searchParams]);
+    const raw = sessionStorage.getItem(INSTL_SNCN_REGISTER_SELECTION_KEY);
+    if (!raw) return;
+
+    try {
+      const parsed = JSON.parse(raw) as { taskSeComCd?: string; taskSeComCdNm?: string };
+      setTaskSeComCd(parsed.taskSeComCd || "RE");
+      setTaskSeComCdNm(parsed.taskSeComCdNm || "재이용수");
+    } catch {
+      // noop
+    } finally {
+      sessionStorage.removeItem(INSTL_SNCN_REGISTER_SELECTION_KEY);
+    }
+  }, []);
 
   /* ── 기본 정보 ── */
   const [bzNm, setBzNm] = useState("");