diff --git a/cdk/po_stack.py b/cdk/po_stack.py
index 4648842..787ce07 100644
--- a/cdk/po_stack.py
+++ b/cdk/po_stack.py
@@ -157,6 +157,21 @@ class PoIngestStack(Stack):
             enforce_ssl=True,
         )
 
+        # --- Explicit log group (INFRA-114) ---
+        # Replaces the deprecated log_retention prop, which provisioned a
+        # LogRetention custom resource whose role held logs:PutRetentionPolicy/
+        # DeleteRetentionPolicy on Resource "*" (checkov CKV_AWS_111). The name
+        # matches Lambda's default (/aws/lambda/<function-name>) so the function
+        # keeps writing to the same group; RETAIN matches the repo convention for
+        # stateful resources.
+        email_processor_log_group = logs.LogGroup(
+            self,
+            "EmailProcessorLogGroup",
+            log_group_name="/aws/lambda/po-email-processor",
+            retention=logs.RetentionDays.TWO_MONTHS,
+            removal_policy=RemovalPolicy.RETAIN,
+        )
+
         # --- Lambda function ---
         email_processor = lambda_.Function(
             self,
@@ -180,7 +195,7 @@ class PoIngestStack(Stack):
             ),
             timeout=Duration.seconds(60),
             memory_size=256,
-            log_retention=logs.RetentionDays.TWO_MONTHS,
+            log_group=email_processor_log_group,
             dead_letter_queue=email_processor_dlq,
             environment={
                 "PO_TABLE": "purchase-orders",
@@ -297,6 +312,14 @@ class PoIngestStack(Stack):
         )
 
         # --- Web UI Lambda ---
+        web_ui_log_group = logs.LogGroup(
+            self,
+            "WebUILogGroup",
+            log_group_name="/aws/lambda/po-web-ui",
+            retention=logs.RetentionDays.TWO_MONTHS,
+            removal_policy=RemovalPolicy.RETAIN,
+        )
+
         web_ui = lambda_.Function(
             self,
             "WebUI",
@@ -307,7 +330,7 @@ class PoIngestStack(Stack):
             code=lambda_.Code.from_asset("../lambdas/po/web_ui"),
             timeout=Duration.seconds(60),
             memory_size=256,
-            log_retention=logs.RetentionDays.TWO_MONTHS,
+            log_group=web_ui_log_group,
             environment={
                 "PO_TABLE": "purchase-orders",
             },
@@ -369,6 +392,14 @@ class PoIngestStack(Stack):
         # 518 WCU of write amplification. Re-add if a state-level query path ships.
 
         # --- Site extractor Lambda (DynamoDB Streams → verified-sites) ---
+        site_extractor_log_group = logs.LogGroup(
+            self,
+            "SiteExtractorLogGroup",
+            log_group_name="/aws/lambda/po-ingest-site-extractor",
+            retention=logs.RetentionDays.TWO_MONTHS,
+            removal_policy=RemovalPolicy.RETAIN,
+        )
+
         site_extractor = lambda_.Function(
             self,
             "SiteExtractor",
@@ -379,7 +410,7 @@ class PoIngestStack(Stack):
             code=lambda_.Code.from_asset("../lambdas/po/site_extractor"),
             timeout=Duration.seconds(60),
             memory_size=256,
-            log_retention=logs.RetentionDays.TWO_MONTHS,
+            log_group=site_extractor_log_group,
             environment={
                 "VERIFIED_SITES_TABLE": verified_sites_table.table_name,
                 "PENDING_REVIEW_TABLE": "pending-site-review",
diff --git a/cdk/wo_stack.py b/cdk/wo_stack.py
index fc8d166..e1cb926 100644
--- a/cdk/wo_stack.py
+++ b/cdk/wo_stack.py
@@ -156,6 +156,21 @@ class WorkorderIngestStack(Stack):
             enforce_ssl=True,
         )
 
+        # --- Explicit log group (INFRA-114) ---
+        # Replaces the deprecated log_retention prop, which provisioned a
+        # LogRetention custom resource whose role held logs:PutRetentionPolicy/
+        # DeleteRetentionPolicy on Resource "*" (checkov CKV_AWS_111). The name
+        # matches Lambda's default (/aws/lambda/<function-name>) so the function
+        # keeps writing to the same group; RETAIN matches the repo convention for
+        # stateful resources.
+        email_processor_log_group = logs.LogGroup(
+            self,
+            "EmailProcessorLogGroup",
+            log_group_name="/aws/lambda/workorder-email-processor",
+            retention=logs.RetentionDays.TWO_MONTHS,
+            removal_policy=RemovalPolicy.RETAIN,
+        )
+
         # --- Lambda function ---
         email_processor = lambda_.Function(
             self,
@@ -179,7 +194,7 @@ class WorkorderIngestStack(Stack):
             ),
             timeout=Duration.seconds(60),
             memory_size=256,
-            log_retention=logs.RetentionDays.TWO_MONTHS,
+            log_group=email_processor_log_group,
             dead_letter_queue=email_processor_dlq,
             environment={
                 "WORK_ORDERS_TABLE": work_orders_table.table_name,
@@ -311,6 +326,14 @@ class WorkorderIngestStack(Stack):
         )
 
         # --- Web UI Lambda ---
+        web_ui_log_group = logs.LogGroup(
+            self,
+            "WebUILogGroup",
+            log_group_name="/aws/lambda/workorder-web-ui",
+            retention=logs.RetentionDays.TWO_MONTHS,
+            removal_policy=RemovalPolicy.RETAIN,
+        )
+
         web_ui = lambda_.Function(
             self,
             "WebUI",
@@ -321,7 +344,7 @@ class WorkorderIngestStack(Stack):
             code=lambda_.Code.from_asset("../lambdas/wo/web_ui"),
             timeout=Duration.seconds(15),
             memory_size=128,
-            log_retention=logs.RetentionDays.TWO_MONTHS,
+            log_group=web_ui_log_group,
             environment={
                 "WORK_ORDERS_TABLE": work_orders_table.table_name,
                 "COMMENTS_TABLE": comments_table.table_name,