diff --git a/server/routes/webdav.integration.test.ts b/server/routes/webdav.integration.test.ts
index 82f223f4..14b74572 100644
--- a/server/routes/webdav.integration.test.ts
+++ b/server/routes/webdav.integration.test.ts
@@ -47,6 +47,29 @@ async function seedStorage(db: TestApp['db']) {
   `)
 }
 
+async function seedTrafficPlan(db: TestApp['db'], orgId: string, bytes: number, used = 0) {
+  const now = Date.now()
+  await db.run(sql`
+    UPDATE org_quotas
+    SET traffic_used = ${used}, traffic_period = '2026-06'
+    WHERE org_id = ${orgId}
+  `)
+  await db.run(sql`
+    UPDATE org_quota_entitlements
+    SET status = 'revoked', updated_at = ${now}
+    WHERE org_id = ${orgId}
+      AND resource_type = 'traffic'
+      AND entitlement_type = 'plan'
+      AND status = 'active'
+  `)
+  await db.run(sql`
+    INSERT INTO org_quota_entitlements
+      (id, org_id, resource_type, entitlement_type, source, source_id, bytes, starts_at, expires_at, status, metadata, created_at, updated_at)
+    VALUES
+      (${`traffic-plan-${orgId}-${now}`}, ${orgId}, 'traffic', 'plan', 'test', ${`traffic-plan:${orgId}:${now}`}, ${bytes}, ${now}, NULL, 'active', '{"packageName":"Traffic Plan"}', ${now}, ${now})
+  `)
+}
+
 async function org(db: TestApp['db']) {
   const rows = await db.all<{ id: string; slug: string }>(sql`
     SELECT id, slug FROM organization WHERE metadata LIKE '%"type":"personal"%' LIMIT 1
@@ -467,6 +490,113 @@ describe('WebDAV API', () => {
     expect(S3Service.prototype.getObjectBytes).not.toHaveBeenCalled()
   })
 
+  it('GET consumes WebDAV traffic while HEAD does not', async () => {
+    const { app, db, auth } = await createTestApp()
+    await authedHeaders(app)
+    await seedStorage(db)
+    const workspace = await org(db)
+    const account = await userAccount(db)
+    const key = await apiKey(auth, account.id, { webdav: ['read'] })
+    await file(db, workspace.id, { id: 'traffic-full', name: 'traffic.txt', size: 12 })
+    await seedTrafficPlan(db, workspace.id, 1000, 25)
+
+    const head = await app.request(`/dav/${workspace.slug}/traffic.txt`, {
+      method: 'HEAD',
+      headers: basicHeaders(account.email, key),
+    })
+    expect(head.status).toBe(200)
+    const afterHead = await db.all<{ trafficUsed: number }>(
+      sql`SELECT traffic_used AS trafficUsed FROM org_quotas WHERE org_id = ${workspace.id}`,
+    )
+    expect(afterHead[0].trafficUsed).toBe(25)
+
+    const get = await app.request(`/dav/${workspace.slug}/traffic.txt`, {
+      method: 'GET',
+      headers: basicHeaders(account.email, key),
+    })
+    expect(get.status).toBe(200)
+    await expect(get.text()).resolves.toBe('hello webdav')
+
+    const rows = await db.all<{ trafficUsed: number }>(
+      sql`SELECT traffic_used AS trafficUsed FROM org_quotas WHERE org_id = ${workspace.id}`,
+    )
+    expect(rows[0].trafficUsed).toBe(37)
+  })
+
+  it('GET consumes only served WebDAV range bytes and rejects over-quota reads before S3 access', async () => {
+    const { app, db, auth } = await createTestApp()
+    await authedHeaders(app)
+    await seedStorage(db)
+    const workspace = await org(db)
+    const account = await userAccount(db)
+    const key = await apiKey(auth, account.id, { webdav: ['read'] })
+    await file(db, workspace.id, { id: 'traffic-range', name: 'range-traffic.txt', size: 12 })
+    await seedTrafficPlan(db, workspace.id, 30, 25)
+    vi.mocked(S3Service.prototype.getObjectBody).mockResolvedValueOnce(streamBody('hello'))
+
+    const partial = await app.request(`/dav/${workspace.slug}/range-traffic.txt`, {
+      method: 'GET',
+      headers: basicHeaders(account.email, key, { Range: 'bytes=0-4' }),
+    })
+    expect(partial.status).toBe(206)
+    await expect(partial.text()).resolves.toBe('hello')
+
+    const afterPartial = await db.all<{ trafficUsed: number }>(
+      sql`SELECT traffic_used AS trafficUsed FROM org_quotas WHERE org_id = ${workspace.id}`,
+    )
+    expect(afterPartial[0].trafficUsed).toBe(30)
+
+    const over = await app.request(`/dav/${workspace.slug}/range-traffic.txt`, {
+      method: 'GET',
+      headers: basicHeaders(account.email, key, { Range: 'bytes=5-6' }),
+    })
+    expect(over.status).toBe(422)
+    await expect(over.text()).resolves.toBe('Traffic quota exceeded')
+    expect(S3Service.prototype.getObjectBody).toHaveBeenCalledTimes(1)
+
+    const invalid = await app.request(`/dav/${workspace.slug}/range-traffic.txt`, {
+      method: 'GET',
+      headers: basicHeaders(account.email, key, { Range: 'bytes=99-100' }),
+    })
+    expect(invalid.status).toBe(416)
+    const afterInvalid = await db.all<{ trafficUsed: number }>(
+      sql`SELECT traffic_used AS trafficUsed FROM org_quotas WHERE org_id = ${workspace.id}`,
+    )
+    expect(afterInvalid[0].trafficUsed).toBe(30)
+  })
+
+  it('GET reports metered WebDAV traffic for cloud billing', async () => {
+    const { app, db, auth } = await createTestApp()
+    await authedHeaders(app)
+    await seedStorage(db)
+    await db.run(sql`
+      UPDATE storages
+      SET egress_credit_billing_enabled = 1, egress_credit_unit_bytes = 100, egress_credit_per_unit = 2
+      WHERE id = ${storage.id}
+    `)
+    const workspace = await org(db)
+    const account = await userAccount(db)
+    const key = await apiKey(auth, account.id, { webdav: ['read'] })
+    await file(db, workspace.id, { id: 'traffic-report', name: 'report.txt', size: 12 })
+    await seedTrafficPlan(db, workspace.id, 1000, 0)
+
+    const res = await app.request(`/dav/${workspace.slug}/report.txt`, {
+      method: 'GET',
+      headers: basicHeaders(account.email, key),
+    })
+    expect(res.status).toBe(200)
+    await res.text()
+
+    const reports = await db.all<{ source: string; sourceId: string; bytes: number; status: string }>(sql`
+      SELECT source, source_id AS sourceId, bytes, status
+      FROM cloud_traffic_reports
+      WHERE org_id = ${workspace.id}
+    `)
+    expect(reports).toMatchObject([
+      { source: 'webdav_download', sourceId: 'traffic-report', bytes: 12, status: 'skipped_unbound' },
+    ])
+  })
+
   it('GET supports valid byte ranges and rejects invalid ranges', async () => {
     const { app, db, auth } = await createTestApp()
     await authedHeaders(app)
diff --git a/server/routes/webdav.ts b/server/routes/webdav.ts
index e05bafc4..e1a1f45d 100644
--- a/server/routes/webdav.ts
+++ b/server/routes/webdav.ts
@@ -8,6 +8,7 @@ import { user } from '../db/auth-schema'
 import { matters } from '../db/schema'
 import type { Env } from '../middleware/platform'
 import { ApiKeyRateLimitError, verifyApiKeyForPermission } from '../services/api-keys'
+import { consumeTrafficIfQuotaAllows, refundTraffic } from '../services/effective-quota'
 import {
   copyMatter,
   createMatter,
@@ -58,6 +59,7 @@ import {
   workspaceEntry,
   xmlResponse,
 } from '../services/webdav-xml'
+import { reportTrafficForDownload } from './traffic-metering-utils'
 
 const s3 = new S3Service()
 const READ_METHODS = new Set(['OPTIONS', 'PROPFIND', 'GET', 'HEAD'])
@@ -323,6 +325,10 @@ function multipartRangeContentLength(boundary: string, contentType: string, rang
   return contentLength
 }
 
+function rangeContentBytes(ranges: ByteRange[]): number {
+  return ranges.reduce((total, range) => total + range.end - range.start + 1, 0)
+}
+
 function multipartRangeHeader(boundary: string, contentType: string, range: ByteRange, size: number): Uint8Array {
   return new TextEncoder().encode(
     `--${boundary}\r\nContent-Type: ${contentType}\r\nContent-Range: bytes ${range.start}-${range.end}/${size}\r\n\r\n`,
@@ -756,8 +762,9 @@ async function proppatch(c: DavContext, auth: DavAuth): Promise<Response> {
 async function readFile(c: DavContext, auth: DavAuth): Promise<Response> {
   const db = c.get('platform').db
   try {
-    const { matter } = await resolveExistingWebDavPath(db, auth.userId, davPath(c))
+    const { matter, workspace } = await resolveExistingWebDavPath(db, auth.userId, davPath(c))
     if (!matter) throw new WebDavPathError('Not found', 404)
+    if (!workspace) throw new WebDavPathError('Workspace not found', 404)
     if (matter.dirtype !== DirType.FILE) return c.text('Cannot read collection as file', 405)
     const precondition = preconditionResponse(c, matter)
     if (precondition) return precondition
@@ -782,12 +789,22 @@ async function readFile(c: DavContext, auth: DavAuth): Promise<Response> {
       : { action: 'ignore' }
 
     if (rangeRequest.action === 'none' || rangeRequest.action === 'ignore') {
-      const body = await s3.getObjectBody(storage, matter.object)
-      return new Response(fixedLengthResponseBody(body, size), { headers })
+      const trafficError = await reserveWebDavTraffic(c, workspace.id, matter.id, storage, size)
+      if (trafficError) return trafficError
+      try {
+        const body = await s3.getObjectBody(storage, matter.object)
+        return new Response(fixedLengthResponseBody(body, size), { headers })
+      } catch (e) {
+        await refundTraffic(db, workspace.id, size)
+        throw e
+      }
     }
 
     if (rangeRequest.action === 'reject') return rangeNotSatisfiable(size)
     if (rangeRequest.action !== 'serve') throw new Error('Unexpected range request action')
+    const trafficBytes = rangeContentBytes(rangeRequest.ranges)
+    const trafficError = await reserveWebDavTraffic(c, workspace.id, matter.id, storage, trafficBytes)
+    if (trafficError) return trafficError
     if (rangeRequest.ranges.length > 1) {
       const boundary = `zpan-webdav-${matter.id}`
       const contentLength = multipartRangeContentLength(boundary, matter.type, rangeRequest.ranges, size)
@@ -800,7 +817,13 @@ async function readFile(c: DavContext, auth: DavAuth): Promise<Response> {
 
     const [range] = rangeRequest.ranges
     const contentLength = range.end - range.start + 1
-    const body = await s3.getObjectBody(storage, matter.object, `bytes=${range.start}-${range.end}`)
+    let body: BodyInit
+    try {
+      body = await s3.getObjectBody(storage, matter.object, `bytes=${range.start}-${range.end}`)
+    } catch (e) {
+      await refundTraffic(db, workspace.id, contentLength)
+      throw e
+    }
     headers.set('Content-Length', String(contentLength))
     headers.set('Content-Range', `bytes ${range.start}-${range.end}/${size}`)
     return new Response(fixedLengthResponseBody(body, contentLength), { status: 206, headers })
@@ -809,6 +832,26 @@ async function readFile(c: DavContext, auth: DavAuth): Promise<Response> {
   }
 }
 
+async function reserveWebDavTraffic(
+  c: DavContext,
+  orgId: string,
+  matterId: string,
+  storage: S3Storage,
+  bytes: number,
+): Promise<Response | null> {
+  if (bytes <= 0) return null
+  const db = c.get('platform').db
+  const trafficAllowed = await consumeTrafficIfQuotaAllows(db, orgId, bytes)
+  if (!trafficAllowed) return c.text('Traffic quota exceeded', 422)
+  return reportTrafficForDownload(c, {
+    orgId,
+    bytes,
+    storage,
+    source: 'webdav_download',
+    sourceId: matterId,
+  })
+}
+
 async function putFile(c: DavContext, auth: DavAuth): Promise<Response> {
   const db = c.get('platform').db
   try {
diff --git a/server/services/cloud-traffic-metering.ts b/server/services/cloud-traffic-metering.ts
index 64604dfc..bed9778c 100644
--- a/server/services/cloud-traffic-metering.ts
+++ b/server/services/cloud-traffic-metering.ts
@@ -14,6 +14,7 @@ export type TrafficReportSource =
   | 'landing_share'
   | 'image_hosting'
   | 'custom_domain_image'
+  | 'webdav_download'
 
 export class CloudTrafficBlockedError extends Error {
   constructor() {