diff --git a/A00_Common/design/design_structure_ford_calc.ts b/A00_Common/design/design_structure_ford_calc.ts
index afe825847..1bb82b400 100644
--- a/A00_Common/design/design_structure_ford_calc.ts
+++ b/A00_Common/design/design_structure_ford_calc.ts
@@ -25,6 +25,18 @@ export function fordHeightM(designFlowM3s: number | null, widthM: number): numbe
   return section ? Math.ceil(section.depthM * 100 - 1e-9) / 100 : null;
 }
 
+/** 배수유역도가 낡은 동안(요구 328-3) 설계유량 = 옛 유역 측점 값이라 「낡음」으로 가림 · 높이도 안 채움.
+ *  판정은 배수유역 판 하나(`B05_Profile_UI_Drainage_Live` 가 부름) · 바뀌면 열린 폼을 다시 그림. */
+let drainageStale = false;
+// ponytail: 폼마다 하나씩 쌓임(페이지 다시 열 때만 · 떨어진 폼 다시 그림은 헛일) — 많아지면 폼 닫을 때 뺌
+const staleRepaints = new Set<() => void>();
+export const FORD_FLOW_STALE_HINT = "설계유량 낡음 — 배수유역도 [업데이트] 뒤 셈";
+export function setDrainageStale(next: boolean): void {
+  if (drainageStale === next) return;
+  drainageStale = next;
+  staleRepaints.forEach((repaint) => repaint());
+}
+
 /**
  * 월류 폭 ↔ 높이 연동 — 세월교 · 물넘이 포장 한 벌(52-4 · 65-4 · 65-5 · 287-3).
  *   · 폭을 바꾸면 높이 = 필요 수심 · 높이를 비우거나 그 아래로 넣으면 필요 수심으로.
@@ -41,7 +53,8 @@ export function overflowSync(
   let pending = false;
   const values = () => form().state()[box]?.[0] ?? {};
   const width = () => Number(values().width ?? "");
-  const need = (): number | null => fordHeightM(flow(), width());
+  const need = (): number | null => (drainageStale ? null : fordHeightM(flow(), width()));
+  staleRepaints.add(() => form()?.refresh());
   return {
     arm: (fresh: boolean): void => {
       pending = fresh;
@@ -67,7 +80,7 @@ export function overflowSync(
       if (c.id !== box) return [];
       const hint = document.createElement("p");
       hint.className = "b05-structure__flow-hint";
-      hint.textContent = fordHeightHint(flow(), width());
+      hint.textContent = drainageStale ? FORD_FLOW_STALE_HINT : fordHeightHint(flow(), width());
       return [hint];
     },
   };
diff --git a/B05_Profile/B05_Profile_UI_Drainage_Live.ts b/B05_Profile/B05_Profile_UI_Drainage_Live.ts
index 5504e3f80..bd0520232 100644
--- a/B05_Profile/B05_Profile_UI_Drainage_Live.ts
+++ b/B05_Profile/B05_Profile_UI_Drainage_Live.ts
@@ -20,6 +20,7 @@
 import { API_BASE_URL } from "@config/config_frontend";
 import { currentLanguageIndex, ui_locales } from "@ui/ui_template_locale";
 import { createProgressCircle } from "@ui/ui_template_progress";
+import { setDrainageStale } from "../A00_Common/design/design_structure_ford_calc";
 import type { StageFn } from "../A00_Common/design/logic/design_pipeline_types";
 import {
   computeDetailBasins,
@@ -124,6 +125,7 @@ export function createDrainageLive(deps: DrainageLiveDeps): DrainageLive {
 
   const paint = (): void => {
     deps.root.classList.toggle("is-stale", stale);
+    setDrainageStale(stale); // 관 카드 설계유량 가림(요구 328-3)
     update.classList.toggle("is-pending", stale);
     update.disabled = inflight !== null;
     update.textContent = inflight ? "계산 중…" : UPDATE_LABEL;
diff --git a/B05_Profile/B05_Profile_UI_Drainage_Panel.ts b/B05_Profile/B05_Profile_UI_Drainage_Panel.ts
index f91f86466..35c48980e 100644
--- a/B05_Profile/B05_Profile_UI_Drainage_Panel.ts
+++ b/B05_Profile/B05_Profile_UI_Drainage_Panel.ts
@@ -330,8 +330,9 @@ export function createDrainagePanel(callbacks: DrainagePanelCallbacks = {}): Dra
         id: pipe.id,
       })),
     );
-    // 시설 확장 정보(종류·구간·옵션)는 응답이 정본 — 통째로 다시 채운다(기다리던 월류 높이를 먼저 얹음).
-    const fordFilled = fillFordHeights(response.pipe_points, response.basins, fordWaits());
+    // 시설 확장 정보는 응답이 정본 — 통째로 다시 채운다(기다리던 월류 높이 먼저 · 낡은 답이면 뒤로 · 328-3).
+    const fordFilled =
+      !live.stale && fillFordHeights(response.pipe_points, response.basins, fordWaits());
     facilityStore.replaceFromResponse(response.pipe_points);
     if (fordFilled) rememberPipes();
     if (saved?.response === response) saved.request = JSON.stringify(pipeRequest());
diff --git a/B06_Section/B06_Section_UI_Page_Structures_Panel.ts b/B06_Section/B06_Section_UI_Page_Structures_Panel.ts
index 9487f6718..a2501148b 100644
--- a/B06_Section/B06_Section_UI_Page_Structures_Panel.ts
+++ b/B06_Section/B06_Section_UI_Page_Structures_Panel.ts
@@ -118,6 +118,17 @@ export function createB06StructuresPanel(deps: B06StructuresPanelDeps): B06Struc
       ? inside.reduce((best, at) => (Math.abs(at - anchor) < Math.abs(best - anchor) ? at : best))
       : anchor;
   };
+  /** 담당 유역 설계유량 — 배수유역도 지금 답(관 보고 `shared.lastPipes`)이 먼저 · 아직 없으면 저장 유역
+   *  ([업데이트] 뒤 B06 폼도 새 값 · 낡은 동안 가림은 `design_structure_ford_calc` · 요구 328-3). */
+  const flowAt = (
+    chainageM: number,
+    basins: ReadonlyArray<{ chainage_m: number; design_flow_m3s?: number | null }> = [],
+  ): number | null => {
+    const near = (entry: { chainage_m: number }) =>
+      Math.abs(entry.chainage_m - chainageM) < PIPE_MATCH_M;
+    const live = deps.shared.lastPipes;
+    return (live ? live.find(near) : basins.find(near))?.design_flow_m3s ?? null;
+  };
   /** 종단 알약 레인에 올릴 목록 — 구조물 정본 + 관 정본(가상 구조물). 알약 · 측점선 · 관 id 장부 = 페이지
    *  시설 줄 한 벌(462 · 숨은 B05 평면 마커도 따라감) · `carryEdits` = 사용자 고침(불러옴은 false). */
   const pushMarks = (carryEdits = true): void => {
@@ -353,10 +364,7 @@ export function createB06StructuresPanel(deps: B06StructuresPanelDeps): B06Struc
         // 담당 유역의 설계유량 — 물넘이·세월교 개략 단면(필요 수심 = 월류 높이
         // 자동값)이 이 값에서 나온다. B05와 같은 규칙으로 유역을 측점으로 짝짓는다
         // (2026-08-30 사용자: 월류 폭을 넣어도 높이가 자동 계산되지 않았다).
-        design_flow_m3s:
-          pipeResponse.basins.find(
-            (basin) => Math.abs(basin.chainage_m - pipe.chainage_m) < PIPE_MATCH_M,
-          )?.design_flow_m3s ?? null,
+        design_flow_m3s: flowAt(pipe.chainage_m, pipeResponse.basins),
       }));
       // 옛 소수 관 자리 = 정수 m 초안(요구 167 · B05 `snapOldStations` 와 같은 셈) — B06 을 바로 열어도
       // 카드 · 측점이 B05 를 거친 것과 같음 · 정본은 [저장]에서
@@ -549,9 +557,16 @@ export function createB06StructuresPanel(deps: B06StructuresPanelDeps): B06Struc
         entry.options = { ...entry.options, ford_height_m: height };
         return true;
       });
-      if (!filled.length) return;
+      // 설계유량도 새 답으로(요구 328-3)
+      const flowed = pipeFacilities.filter((entry) => {
+        const flow = flowAt(entry.chainage_m);
+        if (!deps.shared.lastPipes || flow === (entry.design_flow_m3s ?? null)) return false;
+        entry.design_flow_m3s = flow;
+        return true;
+      });
+      if (!filled.length && !flowed.length) return;
       section.setPipeFacilities(pipeFacilities);
-      const open = filled.find((entry) => entry.chainage_m === currentChainageM);
+      const open = [...filled, ...flowed].find((entry) => entry.chainage_m === currentChainageM);
       if (open) section.selectPipeByChainage(open.chainage_m);
     },
     releasePipe: () => {
diff --git a/B06_Section/B06_Section_UI_Section_View_Profile.ts b/B06_Section/B06_Section_UI_Section_View_Profile.ts
index 71b5e9c2b..4aaea35c4 100644
--- a/B06_Section/B06_Section_UI_Section_View_Profile.ts
+++ b/B06_Section/B06_Section_UI_Section_View_Profile.ts
@@ -183,6 +183,7 @@ export function createSectionProfile(
                 p.facility,
                 p.options?.pipe_diameter_mm ?? null,
                 p.options?.ford_height_m ?? null,
+                p.design_flow_m3s ?? null, // [업데이트] 뒤 설계유량(요구 328-3)
               ]),
             );
             const changed = pipeSignature !== null && signature !== pipeSignature;
diff --git a/resources/tester/helper_514_2_stale_flow.cjs b/resources/tester/helper_514_2_stale_flow.cjs
new file mode 100644
index 000000000..cb34fa0cf
--- /dev/null
+++ b/resources/tester/helper_514_2_stale_flow.cjs
@@ -0,0 +1,62 @@
+/* 514-2 낡은 유량 가림 헬퍼 — 진짜 `design_structure_ford_calc.ts` 를 Node 로 돌려 JSON 한 벌로(요구 328-3). */
+const fs = require("fs");
+const path = require("path");
+const ts = require(path.join(__dirname, "..", "..", "config", "node_modules", "typescript"));
+
+const ROOT = path.join(__dirname, "..", "..");
+const cache = new Map();
+const load = (file) => {
+  if (cache.has(file)) return cache.get(file);
+  const js = ts.transpileModule(fs.readFileSync(file, "utf8"), {
+    compilerOptions: { module: ts.ModuleKind.CommonJS, target: ts.ScriptTarget.ES2020 },
+  }).outputText;
+  const box = { exports: {} };
+  cache.set(file, box.exports);
+  const near = (m) => {
+    if (m.startsWith("@config/")) return load(path.join(ROOT, "config", `${m.slice(8)}.ts`));
+    if (m.startsWith(".")) return load(path.join(path.dirname(file), `${m}.ts`));
+    return new Proxy({}, { get: () => () => {} });
+  };
+  new Function("exports", "module", "require", js)(box.exports, box, near);
+  return box.exports;
+};
+const calc = load(path.join(ROOT, "A00_Common", "design", "design_structure_ford_calc.ts"));
+
+globalThis.document = { createElement: () => ({ textContent: "", className: "" }) };
+const state = { ford: [{ width: "10", height: "" }] };
+let refreshed = 0;
+const form = {
+  state: () => state,
+  setValue: (c, i, v) => (state[c][0][i] = v),
+  refresh: () => (refreshed += 1),
+};
+const sync = calc.overflowSync(
+  () => form,
+  "ford",
+  () => 2.54,
+  () => undefined,
+);
+const hint = () => sync.fields({ id: "ford" })[0].textContent;
+const edit = (item, value) => {
+  state.ford[0][item] = value;
+  sync.onChange({ id: "ford" }, { id: item });
+  return state.ford[0].height;
+};
+
+const fresh = { hint: hint(), height: edit("width", "10") };
+calc.setDrainageStale(true);
+state.ford[0].height = "";
+const stale = { refreshed, hint: hint(), height: edit("width", "8") };
+sync.arm(true);
+sync.fill();
+stale.afterFill = state.ford[0].height;
+let before = refreshed;
+calc.setDrainageStale(true); // 같은 값 = 다시 안 그림
+stale.repaintSame = refreshed - before;
+before = refreshed;
+calc.setDrainageStale(false);
+const back = { repaint: refreshed - before, hint: hint() };
+sync.fill();
+back.afterFill = state.ford[0].height;
+
+process.stdout.write(JSON.stringify({ fresh, stale, back }));
diff --git a/resources/tester/test_514_2_stale_flow.py b/resources/tester/test_514_2_stale_flow.py
new file mode 100644
index 000000000..af9726aab
--- /dev/null
+++ b/resources/tester/test_514_2_stale_flow.py
@@ -0,0 +1,60 @@
+"""514-2 배수유역도 낡은 동안 관 카드 설계유량 「낡음」 가림(요구 328-3).
+
+판정 한 곳 = 배수유역 판 `live.stale` → `setDrainageStale` · 세월교 · 물넘이 칸 안내 · 높이 자동값이 그것을 봄.
+"""
+
+import json
+import subprocess
+from pathlib import Path
+
+import pytest
+
+ROOT = Path(__file__).resolve().parents[2]
+HELPER = Path(__file__).with_name("helper_514_2_stale_flow.cjs")
+STALE_HINT = "설계유량 낡음 — 배수유역도 [업데이트] 뒤 셈"
+
+
+def _read(*parts: str) -> str:
+    return (ROOT.joinpath(*parts)).read_text(encoding="utf-8")
+
+
+@pytest.fixture(scope="module")
+def run() -> dict:
+    out = subprocess.run(["node", str(HELPER)], capture_output=True, check=True, cwd=ROOT).stdout
+    return json.loads(out.decode("utf-8"))
+
+
+def test_안_낡으면_값(run):
+    assert run["fresh"]["hint"].startswith("필요 수심 ")
+    assert run["fresh"]["height"] != ""
+
+
+def test_낡으면_가림_높이_안_채움(run):
+    stale = run["stale"]
+    assert stale["refreshed"] == 1  # 열린 폼 다시 그림
+    assert stale["hint"] == STALE_HINT
+    assert stale["height"] == "" and stale["afterFill"] == ""
+    assert stale["repaintSame"] == 0
+
+
+def test_업데이트_뒤_값(run):
+    back = run["back"]
+    assert back["repaint"] == 1
+    assert back["hint"].startswith("필요 수심 ")
+    assert back["afterFill"] != ""  # 기다리던 새 시설 높이 = 그때 채움
+
+
+def test_판정은_배수유역_판_한_곳():
+    live = _read("B05_Profile", "B05_Profile_UI_Drainage_Live.ts")
+    assert "setDrainageStale(stale);" in live
+    panel = _read("B05_Profile", "B05_Profile_UI_Drainage_Panel.ts")
+    assert "!live.stale && fillFordHeights(" in " ".join(panel.split())
+
+
+def test_B06_폼도_업데이트_뒤_새_유량():
+    b06 = " ".join(_read("B06_Section", "B06_Section_UI_Page_Structures_Panel.ts").split())
+    assert "design_flow_m3s: flowAt(pipe.chainage_m, pipeResponse.basins)," in b06
+    assert "const live = deps.shared.lastPipes;" in b06
+    assert "entry.design_flow_m3s = flow;" in b06  # adoptFordHeights 가 새 답 유량을 받음
+    view = _read("B06_Section", "B06_Section_UI_Section_View_Profile.ts")
+    assert "p.design_flow_m3s ?? null," in view  # 유량만 바뀌어도 pipesChanged