diff --git a/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.spec.ts b/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.spec.ts
index 5b30b38622..2d0cc835b7 100644
--- a/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.spec.ts
+++ b/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.spec.ts
@@ -26,13 +26,13 @@ describe(`when features miss cost`, () => {
 describe(`when given GeoJson isn't a FeatureCollection`, () => {
   it(`throws exception`, () => {
     expect(() => sut.extract(fixtures.simpleGeometry())).toThrow(
-      /is supported/,
+      /Only FeatureCollection is supported/,
     );
   });
 });
 
 describe(`when given GeoJson has pu costs`, () => {
-  it(`throws exception`, () => {
+  it(`resolves them`, () => {
     expect(sut.extract(fixtures.geoFeaturesWithData())).toMatchInlineSnapshot(`
       Array [
         Object {
diff --git a/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.ts b/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.ts
index dd21e9560d..0adcf55838 100644
--- a/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.ts
+++ b/api/apps/geoprocessing/src/modules/surface-cost/adapters/extract-pu-cost.ts
@@ -1,4 +1,5 @@
 import { isDefined } from '@marxan/utils';
+import { MaybeProperties } from '@marxan/utils/types';
 import { FeatureCollection, GeoJSON, Geometry } from 'geojson';
 import { PlanningUnitCost } from '../ports/planning-unit-cost';
 import { PuExtractorPort } from '../ports/pu-extractor/pu-extractor.port';
@@ -7,14 +8,15 @@ type Properties = {
   cost: number;
   planningUnitId: string;
 };
-type MaybeProperties = Partial<Properties> | undefined | null;
+
+type MaybeCost = MaybeProperties<Properties>;
 
 export class ExtractPuCost implements PuExtractorPort {
   extract(geo: GeoJSON): PlanningUnitCost[] {
     if (!this.isFeatureCollection(geo)) {
       throw new Error('Only FeatureCollection is supported.');
     }
-    const input: FeatureCollection<Geometry, MaybeProperties> = geo;
+    const input: FeatureCollection<Geometry, MaybeCost> = geo;
 
     const puCosts = input.features
       .map((feature) => feature.properties)
@@ -36,7 +38,7 @@ export class ExtractPuCost implements PuExtractorPort {
     return geo.type === 'FeatureCollection';
   }
 
-  private hasCostValues(properties: MaybeProperties): properties is Properties {
+  private hasCostValues(properties: MaybeCost): properties is Properties {
     return (
       isDefined(properties) &&
       isDefined(properties.cost) &&
diff --git a/api/libs/utils/src/types/index.ts b/api/libs/utils/src/types/index.ts
new file mode 100644
index 0000000000..57cfe27a74
--- /dev/null
+++ b/api/libs/utils/src/types/index.ts
@@ -0,0 +1 @@
+export { MaybeProperties } from './maybe-properties';
diff --git a/api/libs/utils/src/types/maybe-properties.ts b/api/libs/utils/src/types/maybe-properties.ts
new file mode 100644
index 0000000000..c9c2ab203c
--- /dev/null
+++ b/api/libs/utils/src/types/maybe-properties.ts
@@ -0,0 +1 @@
+export type MaybeProperties<T> = Partial<T> | undefined | null;