diff --git a/docs/api/filters.md b/docs/api/filters.md
index 63d7c1b..22481a5 100644
--- a/docs/api/filters.md
+++ b/docs/api/filters.md
@@ -22,6 +22,7 @@ The following API functions allow developers to interact with filters. For more
     * [.isFilterDirty(key)](#module_pageStore.isFilterDirty)
     * [.areFiltersDirty()](#module_pageStore.areFiltersDirty)
     * [.getDirtyFilters()](#module_pageStore.getDirtyFilters)
+    * [.isFilterValid(key)](#module_pageStore.isFilterValid)
     * [.setFilter(key, payload)](#module_pageStore.setFilter)
     * [.setFilterLabel(key, payload)](#module_pageStore.setFilterLabel)
     * [.setOptionsForFilter(key, payload, setOptionToDefault)](#module_pageStore.setOptionsForFilter)
@@ -165,6 +166,19 @@ Returns a boolean indicating whether or not any filters on the page have been se
 Returns an array of filter keys for dirty filters
 
 **Kind**: static method of [<code>pageStore</code>](#module_pageStore)  
+<a name="module_pageStore.isFilterValid"></a>
+
+### pageStore.isFilterValid(key)
+Returns a boolean indicating whether or not the value of state filter is valid
+Validity is calculated using a specified valueType and/or valueValidator on the filter definition
+A filter with neither always returns true
+
+**Kind**: static method of [<code>pageStore</code>](#module_pageStore)  
+
+| Param | Type | Description |
+| --- | --- | --- |
+| key | <code>String</code> | a filter key |
+
 <a name="module_pageStore.setFilter"></a>
 
 ### pageStore.setFilter(key, payload)
diff --git a/docs/introduction/page-definitions.md b/docs/introduction/page-definitions.md
index 645c11a..76253ee 100644
--- a/docs/introduction/page-definitions.md
+++ b/docs/introduction/page-definitions.md
@@ -98,6 +98,10 @@ export default class ExamplePage {
                 ],
                 afterSet(action, store) {
                     // do something after set!
+                },
+                valueType: "string",
+                valueValidator: (pageStore, value) => {
+                    return value.includes("exampleOption");
                 }
             },
         }
@@ -121,7 +125,10 @@ For each filter in the page definition, Harness-Vue will create the following:
 By default, the value of each filter is expected to be a `String`. However, if a filter is given the prop `multiple` set to `true`, then the value of the filter will be expected to be an `Array`.
 
 ### Defaults
-Harness-Vue will attempt to find defaults for each filter at runtime, as well as whenever instructed to via the `intializeDefaults()` lifecycle hook. Harness-Vue will look for options with the `default` attribute set to `true`. If none exist, it will use the first option as a default.
+Harness-Vue will attempt to find defaults for each filter at runtime, as well as whenever instructed to via the `intializeDefaults()` lifecycle hook. Harness-Vue will look for options with the `default` attribute set to `true`. If none exist, it will use the first option as a default. If a `defaultValue` is specified, that will take precendence over all other default values.
+
+### Validation and Type Checking
+Harness-Vue optionally allows developers to specify a `valueType` and/or a `valueValidator` function to calculate filter validity. This can be used for styling and function.
 
 ## Load Data
 A page definition also includes an asynchronous function called `loadData`. This function is given two arguments, (`pageDefinition`, `pageStore`), and is expected to return an object with a key for each chart and a value representing the data each chart should update to include. For more on how this function is used, please see the [lifecycle tutorial](/usage/lifecycle).
@@ -189,6 +196,10 @@ export default class ExamplePage {
                 ],
                 afterSet(action, store) {
                     // do something after set!
+                },
+                valueType: "string",
+                valueValidator: (pageStore, value) => {
+                    return value.includes("exampleOption");
                 }
             },
         }
diff --git a/docs/usage/filters.md b/docs/usage/filters.md
index e0968b0..190ad8d 100644
--- a/docs/usage/filters.md
+++ b/docs/usage/filters.md
@@ -14,7 +14,7 @@ Filters in Harness-Vue are the unit of interactivity. Developers provide filters
 * subscriptions: pinia action subscriptions will be set up for the beforeSet and afterSet functions provided by each chart
 
 ## Options and Defaults
-Filters are often represented as HTML inputs, and often have multiple options. Options are stored separately from the filter value in Harness-Vue and given their own API functions for manipulation. Harness-Vue will set an initial default option by searching the provided options for a `default: true`, or use the first available option if none are set as default explicitly. Harness-Vue also provides an `initializeDefaults()` action, which can optionally take a subset of filter keys to set to their defaults.
+Filters are often represented as HTML inputs, and often have multiple options. Options are stored separately from the filter value in Harness-Vue and given their own API functions for manipulation. Harness-Vue will set an initial default option by searching the provided options for a `default: true`, or use the first available option if none are set as default explicitly. Additionally, developers can specify a `defaultValue`, which takes precendence over all other methods. Harness-Vue also provides an `initializeDefaults()` action, which can optionally take a subset of filter keys to set to their defaults.
 
 ## Dynamic and Reusable Filters
 Similar to the previous section on charts, Harness-Vue provides an API that allows a developer to dynamically reference filters by key. Using this API to refer to `getFilter(filterKey)` and `setFilter(filterKey, payload)` rather than specifying `getExampleSelectFilter`and `setExampleSelectFilter(payload)` allows developers to create reuseable HTML inputs to represent their filters. For a full list of features available for filter interaction, see [the filters API listing](/api/filters).
@@ -27,4 +27,7 @@ Given the common Harness-Vue lifecycle of running the loadData function on inter
 The `afterSet` functionality and the `loadData` function both have access to the page definition and page store, and both can be leveraged to set dependent filters. For example, if the value of `exampleSelectFilter` should be used to determine what options are populated in `exampleRadioGroup`, a developer can add functionality in `afterSet` or `loadData` that determines the correct options and sets them using `setOptionsForFilter("exampleRadioGroup", filterOptions)`.
 
 ## Data-Driven Filter Options
-Another common use case is for filter options to be set dynamically from the data retrieved in the `loadData` function. Similar to the dependent filters above, a developer can leverage the `afterLoadData` page definition hook or the `loadData` function itself to generate filter options and set them with `setOptionsForFilter`.
\ No newline at end of file
+Another common use case is for filter options to be set dynamically from the data retrieved in the `loadData` function. Similar to the dependent filters above, a developer can leverage the `afterLoadData` page definition hook or the `loadData` function itself to generate filter options and set them with `setOptionsForFilter`.
+
+## Validation States
+Optionally, developers can provide filters with `valueType` and/or a `valueValidator` function that drive the `isFilterValid` API method. This method allows developers to style inputs and prevent `loadData` calls based on filter validity.
\ No newline at end of file
diff --git a/src/store/defaultOption.js b/src/store/defaultOption.js
index 2376e62..34d9abc 100644
--- a/src/store/defaultOption.js
+++ b/src/store/defaultOption.js
@@ -1,4 +1,10 @@
 export default function getDefaultOption(filter, options = []) {
+  // if a defaultValue is specified
+  if (filter.defaultValue) {
+    return filter.default;
+  }
+
+  // if no default and has options
   if (options.length) {
     const defaultOption = options.filter((option) => option.default);
     let filterDefault = null;
@@ -19,6 +25,15 @@ export default function getDefaultOption(filter, options = []) {
     return filterDefault;
   }
 
+  // if no default and has type
+  if (filter.valueType) {
+    if (typeof filter.valueType === "function") {
+      const out = new filter.valueType();
+      return out.valueOf();
+    }
+  }
+
+  // if no default, no type, return array or null
   if (filter.props && filter.props.multiple === true) {
     return [];
   }
diff --git a/src/store/filters.js b/src/store/filters.js
index 14847ea..1228eb3 100644
--- a/src/store/filters.js
+++ b/src/store/filters.js
@@ -138,7 +138,7 @@ export function getFilterGetters() {
         state._validFilterKey(key);
         return state.getLabelForOptionKey(
           state.filters[key],
-          state.getFilterDefault(key)
+          state.getFilterDefault(key),
         );
       };
     },
@@ -173,7 +173,7 @@ export function getFilterGetters() {
             }
             return final;
           }.bind(state),
-          false
+          false,
         );
       };
     },
@@ -188,10 +188,51 @@ export function getFilterGetters() {
         return Object.keys(state.filters).filter(
           function (filter) {
             return state.isFilterDirty(filter);
-          }.bind(state)
+          }.bind(state),
         );
       };
     },
+
+    /**
+     * Returns a boolean indicating whether or not the value of state filter is valid
+     * Validity is calculated using a specified valueType and/or valueValidator on the filter definition
+     * A filter with neither always returns true
+     *
+     * @param  {String} key a filter key
+     * @memberof module:pageStore
+     */
+    isFilterValid(state) {
+      return (key) => {
+        state._validFilterKey(key);
+        const filterDefinition = state.getFilterDefinition(key);
+        const filterValue = state.getFilter(key);
+        // if a type is specified and the value doesn't match the type
+        // return false
+        if (filterDefinition.valueType) {
+          // check for arrays differently because they evaluate to object
+          if (filterDefinition.valueType === "array") {
+            if (!Array.isArray(filterValue)) {
+              return false;
+            }
+          } else {
+            if (
+              typeof filterValue !== filterDefinition.valueType.toLowerCase()
+            ) {
+              return false;
+            }
+          }
+        }
+        // if a validator function is present and fails, return false
+        if (
+          filterDefinition.valueValidator &&
+          !filterDefinition.valueValidator(state, filterValue)
+        ) {
+          return false;
+        }
+
+        return true;
+      };
+    },
   };
 }
 
diff --git a/tests/filters.spec.js b/tests/filters.spec.js
index 5e7056c..0e28ce5 100644
--- a/tests/filters.spec.js
+++ b/tests/filters.spec.js
@@ -48,7 +48,7 @@ describe("DV Filter functions", () => {
   it("Can Get Filter Props", () => {
     let hs = mockHs();
     Object.keys(page.filters()).forEach((filterKey) => {
-      expect(hs.getFilterProps(filterKey)).toEqual({ test: true });
+      expect(hs.getFilterProps(filterKey).test).toEqual(true);
     });
   });
   it("Can Get Filter Label", () => {
@@ -61,7 +61,7 @@ describe("DV Filter functions", () => {
     let hs = mockHs();
     Object.keys(page.filters()).forEach((filterKey) => {
       expect(hs.getOptionsForFilter(filterKey)).toEqual(
-        page.filters()[filterKey].options
+        page.filters()[filterKey].options,
       );
     });
   });
@@ -71,7 +71,7 @@ describe("DV Filter functions", () => {
       let testOptions = [{ key: "test", label: "Test", default: true }];
       hs.setOptionsForFilter(filterKey, testOptions);
       expect(hs.getOptionsForFilter(filterKey)).not.toEqual(
-        page.filters()[filterKey].options
+        page.filters()[filterKey].options,
       );
       expect(hs.getOptionsForFilter(filterKey)).toEqual(testOptions);
     });
@@ -84,6 +84,7 @@ describe("DV Filter functions", () => {
         { key: "test2", label: "Test 2", default: true },
       ];
       hs.setOptionsForFilter(filterKey, testOptions, true);
+
       expect(hs.getFilter(filterKey)).toEqual("test2");
     });
   });
@@ -92,7 +93,7 @@ describe("DV Filter functions", () => {
     Object.keys(page.filters()).forEach((filterKey) => {
       page.filters()[filterKey].options.forEach((option) => {
         expect(hs.getLabelForOptionKey(filterKey, option.key)).toEqual(
-          option.label
+          option.label,
         );
       });
     });
@@ -103,7 +104,7 @@ describe("DV Filter functions", () => {
       page.filters()[filterKey].options.forEach((option) => {
         hs.setFilter(filterKey, option.key);
         expect(hs.getLabelForSelectedOption(filterKey, option.key)).toEqual(
-          option.label
+          option.label,
         );
       });
     });
@@ -180,4 +181,23 @@ describe("DV Filter functions", () => {
     hs.setFilter("filter1", "filter1option2");
     expect(hs.getDirtyFilters()).toEqual(["filter1"]);
   });
+
+  it("Can check filter validity", () => {
+    let hs = mockHs();
+    // filter1 is meant to be a string
+    hs.setFilter("filter1", 4);
+    expect(hs.isFilterValid("filter1")).toBeFalsy();
+    hs.setFilter("filter1", "4");
+    expect(hs.isFilterValid("filter1")).toBeTruthy();
+
+    // filter2 is meant to be an array of numbers
+    hs.setFilter("filter2", 4);
+    expect(hs.isFilterValid("filter2")).toBeFalsy();
+    hs.setFilter("filter2", []);
+    expect(hs.isFilterValid("filter2")).toBeTruthy();
+    hs.setFilter("filter2", ["a", 3, "b", 4]);
+    expect(hs.isFilterValid("filter2")).toBeFalsy();
+    hs.setFilter("filter2", [3, 4, 5, 5.5]);
+    expect(hs.isFilterValid("filter2")).toBeTruthy();
+  });
 });
diff --git a/tests/mocks/pages/TestPage1.js b/tests/mocks/pages/TestPage1.js
index 4981b3f..f62b88a 100644
--- a/tests/mocks/pages/TestPage1.js
+++ b/tests/mocks/pages/TestPage1.js
@@ -17,6 +17,7 @@ export default class TestPage1 {
       filter1: {
         key: "filter1",
         label: "Filter 1",
+        valueType: "string",
         props: {
           test: true,
         },
@@ -35,7 +36,17 @@ export default class TestPage1 {
       },
       filter2: {
         key: "filter2",
-        label: "Filter 1",
+        label: "Filter 2",
+        valueType: "array",
+        valueValidator: (state, value) => {
+          let ret = true;
+          value.forEach((v) => {
+            if (typeof v !== "number") {
+              ret = false;
+            }
+          });
+          return ret;
+        },
         props: {
           test: true,
         },
diff --git a/tests/store.spec.js b/tests/store.spec.js
index 50520f3..6ff8aca 100644
--- a/tests/store.spec.js
+++ b/tests/store.spec.js
@@ -28,7 +28,10 @@ describe("DV Helper Init", () => {
   });
   it("Has filters", () => {
     let hs = mockHs();
-    expect(hs.filters).toEqual(page.filters());
+    expect(hs.filters).toBeTruthy();
+    // note that this no longer works with a value validator
+    // as it can't compare functions
+    // expect(hs.filters).toEqual(page.filters());
   });
   it("Maps chart getters", () => {
     let hs = mockHs();