diff --git a/src/main/java/seedu/address/logic/parser/CliSyntax.java b/src/main/java/seedu/address/logic/parser/CliSyntax.java
index 37677eb9863..588a4c2cfaf 100644
--- a/src/main/java/seedu/address/logic/parser/CliSyntax.java
+++ b/src/main/java/seedu/address/logic/parser/CliSyntax.java
@@ -11,6 +11,7 @@ public class CliSyntax {
     public static final Prefix PREFIX_EMAIL = new Prefix("e/");
     public static final Prefix PREFIX_ADDRESS = new Prefix("a/");
     public static final Prefix PREFIX_TAG = new Prefix("t/");
+    public static final Prefix PREFIX_UNITNUMBER = new Prefix("unitNo/");
     public static final Prefix PREFIX_BLOCK = new Prefix("blk/");
     public static final Prefix PREFIX_POSTALCODE = new Prefix("postal/");
 }
diff --git a/src/main/java/seedu/address/logic/parser/ParserUtil.java b/src/main/java/seedu/address/logic/parser/ParserUtil.java
index 795567ea741..be3e9092af8 100644
--- a/src/main/java/seedu/address/logic/parser/ParserUtil.java
+++ b/src/main/java/seedu/address/logic/parser/ParserUtil.java
@@ -11,6 +11,7 @@
 import seedu.address.logic.parser.exceptions.ParseException;
 import seedu.address.model.house.Block;
 import seedu.address.model.house.PostalCode;
+import seedu.address.model.house.UnitNumber;
 import seedu.address.model.person.Address;
 import seedu.address.model.person.Email;
 import seedu.address.model.person.Name;
@@ -125,6 +126,20 @@ public static Set<Tag> parseTags(Collection<String> tags) throws ParseException
         return tagSet;
     }
 
+    /**
+     * Parses a {@code String unitNumber} into a {@code unitNumber}.
+     * Leading and trailing whitespaces will be trimmed.
+     *
+     * @throws ParseException if the given {@code unitNumber} is invalid.
+     */
+    public static UnitNumber parseUnitNumber(String unitNumber) throws ParseException {
+        requireNonNull(unitNumber);
+        String trimmedLevel = unitNumber.trim();
+        if (!UnitNumber.isValidUnitNumber(trimmedLevel)) {
+            throw new ParseException(UnitNumber.MESSAGE_CONSTRAINTS);
+        }
+        return new UnitNumber(trimmedLevel);
+    }
     /**
      * Parses a {@code String block} into an {@code Block}.
      * Leading and trailing whitespaces will be trimmed.
diff --git a/src/main/java/seedu/address/model/house/UnitNumber.java b/src/main/java/seedu/address/model/house/UnitNumber.java
new file mode 100644
index 00000000000..2e2713f7d8e
--- /dev/null
+++ b/src/main/java/seedu/address/model/house/UnitNumber.java
@@ -0,0 +1,64 @@
+package seedu.address.model.house;
+
+import static java.util.Objects.requireNonNull;
+import static seedu.address.commons.util.AppUtil.checkArgument;
+
+/**
+ * Represents a House's unit number in the address book.
+ * Guarantees: immutable; is valid as declared in {@link #isValidUnitNumber(String)}
+ */
+public class UnitNumber {
+
+    public static final String MESSAGE_CONSTRAINTS =
+            "The unit number should only contain numbers, it should be at least 1 digit "
+                    + "and at most 3 digits long, and cannot be '0', '00' or '000'.";
+    public static final String VALIDATION_REGEX = "\\d{1,3}";
+    public static final String ZERO_REGEX = "^0+$";
+
+    public final String value;
+
+    /**
+     * Constructs a {@code UnitNumber}.
+     *
+     * @param unitNumber A valid unit number.
+     */
+    public UnitNumber(String unitNumber) {
+        requireNonNull(unitNumber);
+        checkArgument(isValidUnitNumber(unitNumber), MESSAGE_CONSTRAINTS);
+        value = unitNumber;
+    }
+
+    /**
+     * Returns true if a given string is a valid unit number.
+     *
+     * @param test The string to test.
+     * @return true if the test matches the VALIDATION_REGEX and is not "0".
+     */
+    public static boolean isValidUnitNumber(String test) {
+        return test.matches(VALIDATION_REGEX) && !test.matches(ZERO_REGEX);
+    }
+
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+
+        if (!(other instanceof UnitNumber)) {
+            return false;
+        }
+
+        UnitNumber otherUnitNumber = (UnitNumber) other;
+        return value.equals(otherUnitNumber.value);
+    }
+
+    @Override
+    public int hashCode() {
+        return value.hashCode();
+    }
+}
diff --git a/src/test/java/seedu/address/logic/parser/ParserUtilTest.java b/src/test/java/seedu/address/logic/parser/ParserUtilTest.java
index 76e3df6f996..f363378c13b 100644
--- a/src/test/java/seedu/address/logic/parser/ParserUtilTest.java
+++ b/src/test/java/seedu/address/logic/parser/ParserUtilTest.java
@@ -16,6 +16,7 @@
 import seedu.address.logic.parser.exceptions.ParseException;
 import seedu.address.model.house.Block;
 import seedu.address.model.house.PostalCode;
+import seedu.address.model.house.UnitNumber;
 import seedu.address.model.person.Address;
 import seedu.address.model.person.Email;
 import seedu.address.model.person.Name;
@@ -28,6 +29,7 @@ public class ParserUtilTest {
     private static final String INVALID_ADDRESS = " ";
     private static final String INVALID_EMAIL = "example.com";
     private static final String INVALID_TAG = "#friend";
+    private static final String INVALID_UNIT_NUMBER = "1234";
     private static final String INVALID_BLOCK = "12a34";
     private static final String INVALID_POSTALCODE = "5678990";
 
@@ -38,6 +40,7 @@ public class ParserUtilTest {
     private static final String VALID_POSTALCODE = "654321";
     private static final String VALID_TAG_1 = "friend";
     private static final String VALID_TAG_2 = "neighbour";
+    private static final String VALID_UNIT_NUMBER = "123";
     private static final String VALID_BLOCK = "205A";
 
     private static final String WHITESPACE = " \t\r\n";
@@ -224,6 +227,28 @@ public void parseTags_collectionWithValidTags_returnsTagSet() throws Exception {
     }
 
     @Test
+    public void parseUnitNumber_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> ParserUtil.parseUnitNumber((String) null));
+    }
+
+    @Test
+    public void parseUnitNumber_invalidValue_throwsParseException() {
+        assertThrows(ParseException.class, () -> ParserUtil.parseUnitNumber(INVALID_UNIT_NUMBER));
+    }
+
+    @Test
+    public void parseUnitNumber_validValueWithoutWhitespace_returnsUnitNumber() throws Exception {
+        UnitNumber expectedUnitNumber = new UnitNumber(VALID_UNIT_NUMBER);
+        assertEquals(expectedUnitNumber, ParserUtil.parseUnitNumber(VALID_UNIT_NUMBER));
+    }
+
+    @Test
+    public void parseUnitNumber_validValueWithWhitespace_returnsTrimmedUnitNumber() throws Exception {
+        String unitNumberWithWhitespace = WHITESPACE + VALID_UNIT_NUMBER + WHITESPACE;
+        UnitNumber expectedUnitNumber = new UnitNumber(VALID_UNIT_NUMBER);
+        assertEquals(expectedUnitNumber, ParserUtil.parseUnitNumber(unitNumberWithWhitespace));
+    }
+
     public void parseBlock_null_throwsNullPointerException() {
         assertThrows(NullPointerException.class, () -> ParserUtil.parseBlock((String) null));
     }
diff --git a/src/test/java/seedu/address/model/house/UnitNumberTest.java b/src/test/java/seedu/address/model/house/UnitNumberTest.java
new file mode 100644
index 00000000000..eaeb7b3df5e
--- /dev/null
+++ b/src/test/java/seedu/address/model/house/UnitNumberTest.java
@@ -0,0 +1,64 @@
+package seedu.address.model.house;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static seedu.address.testutil.Assert.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class UnitNumberTest {
+
+    @Test
+    public void constructor_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> new UnitNumber(null));
+    }
+
+    @Test
+    public void constructor_invalidUnitNumber_throwsIllegalArgumentException() {
+        String invalidUnitNumber = "abcd";
+        assertThrows(IllegalArgumentException.class, () -> new UnitNumber(invalidUnitNumber));
+    }
+
+    @Test
+    public void isValidUnitNumber() {
+        // null unit number
+        assertThrows(NullPointerException.class, () -> UnitNumber.isValidUnitNumber(null));
+
+        // invalid unit numbers
+        assertFalse(UnitNumber.isValidUnitNumber("0")); // '0' is invalid
+        assertFalse(UnitNumber.isValidUnitNumber("00")); // '00' is invalid
+        assertFalse(UnitNumber.isValidUnitNumber("000")); // '000' is invalid
+        assertFalse(UnitNumber.isValidUnitNumber("")); // empty string
+        assertFalse(UnitNumber.isValidUnitNumber(" ")); // spaces only
+        assertFalse(UnitNumber.isValidUnitNumber("1234")); // more than 3 digits
+        assertFalse(UnitNumber.isValidUnitNumber("ab")); // non-numeric
+        assertFalse(UnitNumber.isValidUnitNumber("1a2")); // alphabets within digits
+
+        // valid unit numbers
+        assertTrue(UnitNumber.isValidUnitNumber("1")); // minimum valid number
+        assertTrue(UnitNumber.isValidUnitNumber("01")); // leading 0 is allowed
+        assertTrue(UnitNumber.isValidUnitNumber("10")); // 2 digits
+        assertTrue(UnitNumber.isValidUnitNumber("001")); // 3 digits
+        assertTrue(UnitNumber.isValidUnitNumber("999")); // maximum valid number
+    }
+
+    @Test
+    public void equals() {
+        UnitNumber unitNumber = new UnitNumber("12");
+
+        // same values -> returns true
+        assertTrue(unitNumber.equals(new UnitNumber("12")));
+
+        // same object -> returns true
+        assertTrue(unitNumber.equals(unitNumber));
+
+        // null -> returns false
+        assertFalse(unitNumber.equals(null));
+
+        // different types -> returns false
+        assertFalse(unitNumber.equals(5.0f));
+
+        // different unit number -> returns false
+        assertFalse(unitNumber.equals(new UnitNumber("34")));
+    }
+}