diff --git a/src/app/core/shared/search/search.service.spec.ts b/src/app/core/shared/search/search.service.spec.ts
index 9399065ddf..fe5b495ab0 100644
--- a/src/app/core/shared/search/search.service.spec.ts
+++ b/src/app/core/shared/search/search.service.spec.ts
@@ -26,6 +26,8 @@ import { SearchConfigurationService } from './search-configuration.service';
 import { PaginationServiceStub } from '../../../shared/testing/pagination-service.stub';
 import { RequestEntry } from '../../data/request-entry.model';
 import { Angulartics2 } from 'angulartics2';
+import { SearchFilterConfig } from '../../../shared/search/models/search-filter-config.model';
+import anything = jasmine.anything;
 
 @Component({ template: '' })
 class DummyComponent {
@@ -36,7 +38,7 @@ describe('SearchService', () => {
     let searchService: SearchService;
     const router = new RouterStub();
     const route = new ActivatedRouteStub();
-    const searchConfigService = {paginationID: 'page-id'};
+    const searchConfigService = { paginationID: 'page-id' };
     beforeEach(() => {
       TestBed.configureTestingModule({
         imports: [
@@ -103,7 +105,8 @@ describe('SearchService', () => {
     };
 
     const paginationService = new PaginationServiceStub();
-    const searchConfigService = {paginationID: 'page-id'};
+    const searchConfigService = { paginationID: 'page-id' };
+    const requestService = getMockRequestService();
 
     beforeEach(() => {
       TestBed.configureTestingModule({
@@ -119,7 +122,7 @@ describe('SearchService', () => {
         providers: [
           { provide: Router, useValue: router },
           { provide: RouteService, useValue: routeServiceStub },
-          { provide: RequestService, useValue: getMockRequestService() },
+          { provide: RequestService, useValue: requestService },
           { provide: RemoteDataBuildService, useValue: remoteDataBuildService },
           { provide: HALEndpointService, useValue: halService },
           { provide: CommunityDataService, useValue: {} },
@@ -138,13 +141,13 @@ describe('SearchService', () => {
 
     it('should call the navigate method on the Router with view mode list parameter as a parameter when setViewMode is called', () => {
       searchService.setViewMode(ViewMode.ListElement);
-      expect(paginationService.updateRouteWithUrl).toHaveBeenCalledWith('page-id', ['/search'], {page: 1}, { view: ViewMode.ListElement }
+      expect(paginationService.updateRouteWithUrl).toHaveBeenCalledWith('page-id', ['/search'], { page: 1 }, { view: ViewMode.ListElement }
       );
     });
 
     it('should call the navigate method on the Router with view mode grid parameter as a parameter when setViewMode is called', () => {
       searchService.setViewMode(ViewMode.GridElement);
-      expect(paginationService.updateRouteWithUrl).toHaveBeenCalledWith('page-id', ['/search'], {page: 1}, { view: ViewMode.GridElement }
+      expect(paginationService.updateRouteWithUrl).toHaveBeenCalledWith('page-id', ['/search'], { page: 1 }, { view: ViewMode.GridElement }
       );
     });
 
@@ -191,5 +194,23 @@ describe('SearchService', () => {
         expect((searchService as any).rdb.buildFromHref).toHaveBeenCalledWith(endPoint);
       });
     });
+
+    describe('when getFacetValuesFor is called with a filterQuery', () => {
+      it('should add the encoded filterQuery to the args list', () => {
+        jasmine.getEnv().allowRespy(true);
+        const spyRequest = spyOn((searchService as any), 'request').and.stub();
+        spyOn(requestService, 'send').and.returnValue(true);
+        const searchFilterConfig = new SearchFilterConfig();
+        searchFilterConfig._links = {
+          self: {
+            href: 'https://demo.dspace.org/',
+          },
+        };
+
+        searchService.getFacetValuesFor(searchFilterConfig, 1, undefined, 'filter&Query');
+
+        expect(spyRequest).toHaveBeenCalledWith(anything(), 'https://demo.dspace.org?page=0&size=5&prefix=filter%26Query');
+      });
+    });
   });
 });
diff --git a/src/app/core/shared/search/search.service.ts b/src/app/core/shared/search/search.service.ts
index c8ce4b0348..2b1c6a573b 100644
--- a/src/app/core/shared/search/search.service.ts
+++ b/src/app/core/shared/search/search.service.ts
@@ -271,7 +271,7 @@ export class SearchService implements OnDestroy {
     let href;
     let args: string[] = [];
     if (hasValue(filterQuery)) {
-      args.push(`prefix=${filterQuery}`);
+      args.push(`prefix=${encodeURIComponent(filterQuery)}`);
     }
     if (hasValue(searchOptions)) {
       searchOptions = Object.assign(new PaginatedSearchOptions({}), searchOptions, {