diff --git a/js/id/graph/graph.js b/js/id/graph/graph.js
index f2525daf5..5ef0f54b1 100644
--- a/js/id/graph/graph.js
+++ b/js/id/graph/graph.js
@@ -88,25 +88,39 @@ iD.Graph.prototype = {
     // data into each state. To external consumers, it should appear as if the
     // graph always contained the newly downloaded data.
     rebase: function(entities) {
-        var i, keys;
+        var base = this.base(),
+            i, k, child, id, keys;
         // Merging of data only needed if graph is the base graph
         if (!this.inherited) {
-            _.defaults(this.base().entities, entities);
             for (i in entities) {
-                this._updateCalculated(undefined, entities[i], this.base().parentWays, this.base().parentRels);
+                if (!base.entities[i]) {
+                    base.entities[i] = entities[i];
+                    this._updateCalculated(undefined, entities[i],
+                            base.parentWays, base.parentRels);
+                }
             }
         }
 
         keys = Object.keys(this._parentWays);
         for (i = 0; i < keys.length; i++) {
-            this._parentWays[keys[i]] = _.unique((this._parentWays[keys[i]] || [])
-                    .concat(this.base().parentWays[keys[i]] || []));
+            child = keys[i];
+            for (k = 0; k < base.parentWays[child].length; k++) {
+                id = base.parentWays[child][k];
+                if (this.entity(id) && !_.contains(this._parentWays[child], id)) {
+                    this._parentWays[child].push(id);
+                }
+            }
         }
 
         keys = Object.keys(this._parentRels);
         for (i = 0; i < keys.length; i++) {
-            this._parentRels[keys[i]] = _.unique((this._parentRels[keys[i]] || [])
-                    .concat(this.base().parentRels[keys[i]] || []));
+            child = keys[i];
+            for (k = 0; k < base.parentRels[child].length; k++) {
+                id = base.parentRels[child][k];
+                if (this.entity(id) && !_.contains(this._parentRels[child], id)) {
+                    this._parentRels[child].push(id);
+                }
+            }
         }
     },
 
diff --git a/test/spec/graph/graph.js b/test/spec/graph/graph.js
index 9d918ae04..667cfe149 100644
--- a/test/spec/graph/graph.js
+++ b/test/spec/graph/graph.js
@@ -105,6 +105,16 @@ describe('iD.Graph', function() {
             expect(graph2.parentWays(n)).to.eql([w1, w2, w3]);
         });
 
+        it("avoids re-adding removed parentWays", function() {
+            var n = iD.Node({id: 'n'}),
+                w1 = iD.Way({id: 'w1', nodes: ['n']}),
+                graph = iD.Graph([n, w1]),
+                graph2 = graph.remove(w1);
+            graph.rebase({ 'w1': w1 });
+            graph2.rebase({ 'w1': w1 });
+            expect(graph2.parentWays(n)).to.eql([]);
+        });
+
         it("updates parentRelations", function () {
             var n = iD.Node({id: 'n'}),
                 r1 = iD.Relation({id: 'r1', members: [{id: 'n'}]}),
@@ -117,7 +127,17 @@ describe('iD.Graph', function() {
             expect(graph._parentRels.hasOwnProperty('n')).to.be.false;
         });
 
-        it("updates parentWays for nodes with modified parentWays", function () {
+        it("avoids re-adding removed parentRels", function() {
+            var n = iD.Node({id: 'n'}),
+                r1 = iD.Relation({id: 'r1', members: [{id: 'n'}]}),
+                graph = iD.Graph([n, r1]),
+                graph2 = graph.remove(r1);
+            graph.rebase({ 'w1': r1 });
+            graph2.rebase({ 'w1': r1 });
+            expect(graph2.parentWays(n)).to.eql([]);
+        });
+
+        it("updates parentRels for nodes with modified parentWays", function () {
             var n = iD.Node({id: 'n'}),
                 r1 = iD.Relation({id: 'r1', members: [{id: 'n'}]}),
                 r2 = iD.Relation({id: 'r2', members: [{id: 'n'}]}),
@@ -129,6 +149,7 @@ describe('iD.Graph', function() {
             graph2.rebase({'r3': r3});
             expect(graph2.parentRelations(n)).to.eql([r1, r2, r3]);
         });
+
     });
 
     describe("#remove", function () {