diff --git a/pywr-schema/src/nodes/loss_link.rs b/pywr-schema/src/nodes/loss_link.rs
index 01a24078..3c0c84f6 100644
--- a/pywr-schema/src/nodes/loss_link.rs
+++ b/pywr-schema/src/nodes/loss_link.rs
@@ -26,6 +26,8 @@ pub enum LossFactor {
 
 #[cfg(feature = "core")]
 impl LossFactor {
+    /// Load the loss factor and return a corresponding [`Relationship`] if the loss factor is
+    /// not a constant zero. If a zero is loaded, then `None` is returned.
     pub fn load(
         &self,
         network: &mut pywr_core::network::Network,
@@ -34,7 +36,7 @@ impl LossFactor {
         match self {
             LossFactor::Gross { factor } => {
                 let lf = factor.load(network, args)?;
-                // Handle the case where we a given a zero loss factor
+                // Handle the case where we are given a zero loss factor
                 // The aggregated node does not support zero loss factors so filter them here.
                 if lf.is_constant_zero() {
                     return Ok(None);
@@ -173,6 +175,11 @@ impl LossLinkNode {
 
         if let Some(loss_factor) = &self.loss_factor {
             let factors = loss_factor.load(network, args)?;
+
+            if factors.is_none() {
+                // Loaded a constant zero factor; ensure that the loss node has zero flow
+                network.set_node_max_flow(self.meta.name.as_str(), Self::loss_sub_name(), Some(0.0.into()))?;
+            }
             network.set_aggregated_node_relationship(self.meta.name.as_str(), Self::agg_sub_name(), factors)?;
         }
 
@@ -289,7 +296,7 @@ mod tests {
     }
 
     #[test]
-    fn test_model_schema() {
+    fn test_loss_link1_schema() {
         let data = loss_link1_str();
         let schema: PywrModel = serde_json::from_str(data).unwrap();
 
@@ -299,7 +306,7 @@ mod tests {
 
     #[test]
     #[cfg(feature = "core")]
-    fn test_model_run() {
+    fn test_loss_link1_run() {
         let data = loss_link1_str();
         let schema: PywrModel = serde_json::from_str(data).unwrap();
         let temp_dir = TempDir::new().unwrap();
@@ -314,4 +321,40 @@ mod tests {
         // Test all solvers
         run_all_solvers(&model, &[], &expected_outputs);
     }
+
+    fn loss_link2_str() -> &'static str {
+        include_str!("../test_models/loss_link2.json")
+    }
+
+    #[cfg(feature = "core")]
+    fn loss_link2_outputs_str() -> &'static str {
+        include_str!("../test_models/loss_link2-expected.csv")
+    }
+
+    #[test]
+    fn test_loss_link2_schema() {
+        let data = loss_link2_str();
+        let schema: PywrModel = serde_json::from_str(data).unwrap();
+
+        assert_eq!(schema.network.nodes.len(), 4);
+        assert_eq!(schema.network.edges.len(), 3);
+    }
+
+    #[test]
+    #[cfg(feature = "core")]
+    fn test_loss_link2_run() {
+        let data = loss_link2_str();
+        let schema: PywrModel = serde_json::from_str(data).unwrap();
+        let temp_dir = TempDir::new().unwrap();
+
+        let model = schema.build_model(None, Some(temp_dir.path())).unwrap();
+        // After model run there should be an output file.
+        let expected_outputs = [ExpectedOutputs::new(
+            temp_dir.path().join("loss_link2.csv"),
+            loss_link2_outputs_str(),
+        )];
+
+        // Test all solvers
+        run_all_solvers(&model, &[], &expected_outputs);
+    }
 }
diff --git a/pywr-schema/src/nodes/water_treatment_works.rs b/pywr-schema/src/nodes/water_treatment_works.rs
index 846f4ade..a827b981 100644
--- a/pywr-schema/src/nodes/water_treatment_works.rs
+++ b/pywr-schema/src/nodes/water_treatment_works.rs
@@ -181,6 +181,10 @@ impl WaterTreatmentWorks {
 
         if let Some(loss_factor) = &self.loss_factor {
             let factors = loss_factor.load(network, args)?;
+            if factors.is_none() {
+                // Loaded a constant zero factor; ensure that the loss node has zero flow
+                network.set_node_max_flow(self.meta.name.as_str(), Self::loss_sub_name(), Some(0.0.into()))?;
+            }
             network.set_aggregated_node_relationship(self.meta.name.as_str(), Self::agg_sub_name(), factors)?;
         }
 
@@ -255,7 +259,7 @@ mod tests {
     }
 
     #[test]
-    fn test_model_schema() {
+    fn test_wtw1_schema() {
         let data = wtw1_str();
         let schema: PywrModel = serde_json::from_str(data).unwrap();
 
@@ -265,7 +269,7 @@ mod tests {
 
     #[test]
     #[cfg(feature = "core")]
-    fn test_model_run() {
+    fn test_wtw1_run() {
         let data = wtw1_str();
         let schema: PywrModel = serde_json::from_str(data).unwrap();
         let temp_dir = TempDir::new().unwrap();
@@ -285,4 +289,45 @@ mod tests {
         // Test all solvers
         run_all_solvers(&model, &[], &expected_outputs);
     }
+
+    fn wtw2_str() -> &'static str {
+        include_str!("../test_models/wtw2.json")
+    }
+
+    #[cfg(feature = "core")]
+    fn wtw2_outputs_str() -> &'static str {
+        include_str!("../test_models/wtw2-expected.csv")
+    }
+
+    #[test]
+    fn test_wtw2_schema() {
+        let data = wtw2_str();
+        let schema: PywrModel = serde_json::from_str(data).unwrap();
+
+        assert_eq!(schema.network.nodes.len(), 4);
+        assert_eq!(schema.network.edges.len(), 3);
+    }
+
+    #[test]
+    #[cfg(feature = "core")]
+    fn test_wtw2_run() {
+        let data = wtw2_str();
+        let schema: PywrModel = serde_json::from_str(data).unwrap();
+        let temp_dir = TempDir::new().unwrap();
+
+        let mut model = schema.build_model(None, Some(temp_dir.path())).unwrap();
+
+        let network = model.network_mut();
+        assert_eq!(network.nodes().len(), 7);
+        assert_eq!(network.edges().len(), 7);
+
+        // After model run there should be an output file.
+        let expected_outputs = [ExpectedOutputs::new(
+            temp_dir.path().join("wtw2.csv"),
+            wtw2_outputs_str(),
+        )];
+
+        // Test all solvers
+        run_all_solvers(&model, &[], &expected_outputs);
+    }
 }
diff --git a/pywr-schema/src/test_models/loss_link2-expected.csv b/pywr-schema/src/test_models/loss_link2-expected.csv
new file mode 100644
index 00000000..e2dab0f7
--- /dev/null
+++ b/pywr-schema/src/test_models/loss_link2-expected.csv
@@ -0,0 +1,13 @@
+time_start,time_end,scenario_index,metric_set,name,attribute,value
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,loss1,Inflow,10.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,loss1,Outflow,10.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,loss1,Loss,0.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,spill1,Inflow,5.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,loss1,Inflow,10.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,loss1,Outflow,10.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,loss1,Loss,0.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,spill1,Inflow,5.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,loss1,Inflow,10.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,loss1,Outflow,10.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,loss1,Loss,0.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,spill1,Inflow,5.0
diff --git a/pywr-schema/src/test_models/loss_link2.json b/pywr-schema/src/test_models/loss_link2.json
new file mode 100644
index 00000000..e233e7ac
--- /dev/null
+++ b/pywr-schema/src/test_models/loss_link2.json
@@ -0,0 +1,116 @@
+{
+  "metadata": {
+    "title": "Loss Link Test 1",
+    "description": "Test LossLink with zero loss",
+    "minimum_version": "0.1"
+  },
+  "timestepper": {
+    "start": "2015-01-01",
+    "end": "2015-01-03",
+    "timestep": 1
+  },
+  "network": {
+    "nodes": [
+      {
+        "meta": {
+          "name": "input1"
+        },
+        "type": "Catchment",
+        "flow": {
+          "type": "Constant",
+          "value": 15.0
+        }
+      },
+      {
+        "meta": {
+          "name": "loss1"
+        },
+        "type": "LossLink",
+        "loss_factor": {
+          "type": "Net",
+          "factor": {
+            "type": "Constant",
+            "value": 0.0
+          }
+        }
+      },
+      {
+        "meta": {
+          "name": "demand1"
+        },
+        "type": "Output",
+        "max_flow": {
+          "type": "Constant",
+          "value": 10.0
+        },
+        "cost": {
+          "type": "Constant",
+          "value": -10
+        }
+      },
+      {
+        "meta": {
+          "name": "spill1"
+        },
+        "type": "Output",
+        "cost": {
+          "type": "Constant",
+          "value": 10
+        }
+      }
+    ],
+    "edges": [
+      {
+        "from_node": "input1",
+        "to_node": "loss1"
+      },
+      {
+        "from_node": "loss1",
+        "to_node": "demand1"
+      },
+      {
+        "from_node": "input1",
+        "to_node": "spill1"
+      }
+    ],
+    "metric_sets": [
+      {
+        "name": "nodes",
+        "metrics": [
+          {
+            "type": "Node",
+            "name": "loss1",
+            "attribute": "Inflow"
+          },
+          {
+            "type": "Node",
+            "name": "loss1",
+            "attribute": "Outflow"
+          },
+          {
+            "type": "Node",
+            "name": "loss1",
+            "attribute": "Loss"
+          },
+          {
+            "type": "Node",
+            "name": "spill1",
+            "attribute": "Inflow"
+          }
+        ]
+      }
+    ],
+    "outputs": [
+      {
+        "name": "node-outputs",
+        "type": "CSV",
+        "format": "long",
+        "filename": "loss_link2.csv",
+        "metric_set": [
+          "nodes"
+        ],
+        "decimal_places": 1
+      }
+    ]
+  }
+}
diff --git a/pywr-schema/src/test_models/wtw2-expected.csv b/pywr-schema/src/test_models/wtw2-expected.csv
new file mode 100644
index 00000000..ac13113c
--- /dev/null
+++ b/pywr-schema/src/test_models/wtw2-expected.csv
@@ -0,0 +1,13 @@
+time_start,time_end,scenario_index,metric_set,name,attribute,value
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,wtw1,Inflow,10.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,wtw1,Outflow,10.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,wtw1,Loss,0.0
+2015-01-01T00:00:00,2015-01-02T00:00:00,0,nodes,spill1,Inflow,10.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,wtw1,Inflow,10.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,wtw1,Outflow,10.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,wtw1,Loss,0.0
+2015-01-02T00:00:00,2015-01-03T00:00:00,0,nodes,spill1,Inflow,10.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,wtw1,Inflow,10.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,wtw1,Outflow,10.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,wtw1,Loss,0.0
+2015-01-03T00:00:00,2015-01-04T00:00:00,0,nodes,spill1,Inflow,10.0
diff --git a/pywr-schema/src/test_models/wtw2.json b/pywr-schema/src/test_models/wtw2.json
new file mode 100644
index 00000000..bce185c2
--- /dev/null
+++ b/pywr-schema/src/test_models/wtw2.json
@@ -0,0 +1,116 @@
+{
+  "metadata": {
+    "title": "WTW Test 1",
+    "description": "Test WTW work",
+    "minimum_version": "0.1"
+  },
+  "timestepper": {
+    "start": "2015-01-01",
+    "end": "2015-01-03",
+    "timestep": 1
+  },
+  "network": {
+    "nodes": [
+      {
+        "meta": {
+          "name": "input1"
+        },
+        "type": "Catchment",
+        "flow": {
+          "type": "Constant",
+          "value": 20.0
+        }
+      },
+      {
+        "meta": {
+          "name": "wtw1"
+        },
+        "type": "WaterTreatmentWorks",
+        "max_flow": {
+          "type": "Constant",
+          "value": 10.0
+        },
+        "loss_factor": {
+          "type": "Net",
+          "factor": {
+            "type": "Constant",
+            "value": 0.0
+          }
+        }
+      },
+      {
+        "meta": {
+          "name": "demand1"
+        },
+        "type": "Output",
+        "cost": {
+          "type": "Constant",
+          "value": -10
+        }
+      },
+      {
+        "meta": {
+          "name": "spill1"
+        },
+        "type": "Output",
+        "cost": {
+          "type": "Constant",
+          "value": 10
+        }
+      }
+    ],
+    "edges": [
+      {
+        "from_node": "input1",
+        "to_node": "wtw1"
+      },
+      {
+        "from_node": "wtw1",
+        "to_node": "demand1"
+      },
+      {
+        "from_node": "input1",
+        "to_node": "spill1"
+      }
+    ],
+    "metric_sets": [
+      {
+        "name": "nodes",
+        "metrics": [
+          {
+            "type": "Node",
+            "name": "wtw1",
+            "attribute": "Inflow"
+          },
+          {
+            "type": "Node",
+            "name": "wtw1",
+            "attribute": "Outflow"
+          },
+          {
+            "type": "Node",
+            "name": "wtw1",
+            "attribute": "Loss"
+          },
+          {
+            "type": "Node",
+            "name": "spill1",
+            "attribute": "Inflow"
+          }
+        ]
+      }
+    ],
+    "outputs": [
+      {
+        "name": "node-outputs",
+        "type": "CSV",
+        "format": "long",
+        "filename": "wtw2.csv",
+        "metric_set": [
+          "nodes"
+        ],
+        "decimal_places": 1
+      }
+    ]
+  }
+}