diff --git a/etc/ci/buildbot_steps.yml b/etc/ci/buildbot_steps.yml
index 0b6ae34f92b9..19d67c02f25f 100644
--- a/etc/ci/buildbot_steps.yml
+++ b/etc/ci/buildbot_steps.yml
@@ -55,15 +55,15 @@ linux-dev:
   - bash ./etc/ci/check_no_panic.sh
 
 linux-rel-wpt:
-  - ./mach build --release
+  - ./mach build --release --with-debug-assertions
   - ./mach test-wpt-failure
   - ./mach test-wpt --release --processes 24 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log
   - ./mach test-wpt --release --binary-arg=--multiprocess --processes 24 --log-raw test-wpt-mp.log --log-errorsummary wpt-mp-errorsummary.log eventsource
 
 linux-rel-css:
-  - ./mach build --release
+  - ./mach build --release --with-debug-assertions
   - ./mach test-css --release --processes 16 --log-raw test-css.log --log-errorsummary css-errorsummary.log
-  - ./mach build-cef --release
+  - ./mach build-cef --release --with-debug-assertions
   - ./mach build-geckolib --release
   - ./mach test-stylo --release
   - bash ./etc/ci/lockfile_changed.sh
diff --git a/python/servo/build_commands.py b/python/servo/build_commands.py
index 8f05c3e3376f..b78a286be61d 100644
--- a/python/servo/build_commands.py
+++ b/python/servo/build_commands.py
@@ -153,8 +153,13 @@ class MachCommands(CommandBase):
                      help='Print verbose output')
     @CommandArgument('params', nargs='...',
                      help="Command-line arguments to be passed through to Cargo")
+    @CommandArgument('--with-debug-assertions',
+                     default=None,
+                     action='store_true',
+                     help='Enable debug assertions in release')
     def build(self, target=None, release=False, dev=False, jobs=None,
-              features=None, android=None, verbose=False, debug_mozjs=False, params=None):
+              features=None, android=None, verbose=False, debug_mozjs=False, params=None,
+              with_debug_assertions=False):
         if android is None:
             android = self.config["build"]["android"]
         features = features or self.servo_features()
@@ -217,10 +222,7 @@ def build(self, target=None, release=False, dev=False, jobs=None,
         build_start = time()
         env = self.build_env(target=target, is_build=True)
 
-        # TODO: If this ends up making it, we should probably add a
-        # --release-with-debug-assertions option or similar, so it's easier to
-        # build locally.
-        if env.get("SERVO_ENABLE_DEBUG_ASSERTIONS", None):
+        if with_debug_assertions:
             env["RUSTFLAGS"] = "-C debug_assertions"
 
         if android:
@@ -339,7 +341,12 @@ def build(self, target=None, release=False, dev=False, jobs=None,
     @CommandArgument('--release', '-r',
                      action='store_true',
                      help='Build in release mode')
-    def build_cef(self, jobs=None, verbose=False, release=False):
+    @CommandArgument('--with-debug-assertions',
+                     default=None,
+                     action='store_true',
+                     help='Enable debug assertions in release')
+    def build_cef(self, jobs=None, verbose=False, release=False,
+                  with_debug_assertions=False):
         self.ensure_bootstrapped()
 
         ret = None
@@ -358,10 +365,7 @@ def build_cef(self, jobs=None, verbose=False, release=False):
         build_start = time()
         env = self.build_env(is_build=True)
 
-        # TODO: If this ends up making it, we should probably add a
-        # --release-with-debug-assertions option or similar, so it's easier to
-        # build locally.
-        if env.get("SERVO_ENABLE_DEBUG_ASSERTIONS", None):
+        if with_debug_assertions:
             env["RUSTFLAGS"] = "-C debug_assertions"
 
         with cd(path.join("ports", "cef")):