Add South Carolina homestead property tax exemption

changelog.d/8311.added.md

@@ -0,0 +1 @@
+Added the South Carolina Homestead Exemption property tax reduction.

policyengine_us/parameters/gov/states/household/state_property_tax_credits.yaml

@@ -114,6 +114,26 @@ values:
     - wi_homestead_credit
     - wi_property_tax_credit
     - wv_homestead_excess_property_tax_credit
+  2025-01-01:
+    - az_property_tax_credit
+    - ct_property_tax_credit
+    - dc_ptc
+    - il_property_tax_credit
+    - ma_senior_circuit_breaker
+    - me_property_tax_fairness_credit
+    - mi_homestead_property_tax_credit
+    - mo_property_tax_credit
+    - mt_elderly_homeowner_or_renter_credit
+    - mt_property_tax_rebate
+    - nj_property_tax_credit
+    - nm_property_tax_rebate
+    - ny_real_property_tax_credit
+    - ok_ptc
+    - ri_property_tax_credit
+    - sc_homestead_property_tax_reduction
+    - wi_homestead_credit
+    - wi_property_tax_credit
+    - wv_homestead_excess_property_tax_credit
 
 metadata:
   unit: list

policyengine_us/parameters/gov/states/sc/tax/property/homestead_exemption/age_threshold.yaml

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+description: South Carolina limits age-based eligibility to filers at or above this age under the Homestead Exemption program.
+values:
+  2025-01-01: 65
+metadata:
+  unit: year
+  period: year
+  label: South Carolina homestead exemption age threshold
+  reference:
+    - title: South Carolina Department of Revenue | Exempt Property
+      href: https://dor.sc.gov/property/exempt-property

policyengine_us/parameters/gov/states/sc/tax/property/homestead_exemption/amount.yaml

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+description: South Carolina provides this fair market value exemption amount under the Homestead Exemption program.
+values:
+  2025-01-01: 50_000
+metadata:
+  unit: currency-USD
+  period: year
+  label: South Carolina homestead exemption amount
+  reference:
+    - title: South Carolina Department of Revenue | Exempt Property
+      href: https://dor.sc.gov/property/exempt-property

policyengine_us/parameters/gov/states/sc/tax/property/homestead_exemption/assessment_rate.yaml

@@ -0,0 +1,10 @@
+description: South Carolina assesses legal residence value at this rate under the Homestead Exemption program.
+values:
+  2025-01-01: 0.04
+metadata:
+  unit: /1
+  period: year
+  label: South Carolina homestead exemption legal residence assessment rate
+  reference:
+    - title: South Carolina Department of Revenue | Exempt Property
+      href: https://dor.sc.gov/property/exempt-property

policyengine_us/tests/policy/baseline/gov/states/sc/tax/property/homestead_exemption/sc_homestead_exemption.yaml

@@ -0,0 +1,33 @@
+- name: Case 1, exemption is capped at the statutory amount.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+        assessed_property_value: 8_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption: 2_000
+
+- name: Case 2, exemption is limited to assessed property value.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+        assessed_property_value: 1_600
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption: 1_600

policyengine_us/tests/policy/baseline/gov/states/sc/tax/property/homestead_exemption/sc_homestead_exemption_eligible.yaml

@@ -0,0 +1,85 @@
+- name: Case 1, senior homeowner is eligible.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+        assessed_property_value: 8_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption_eligible: true
+
+- name: Case 2, disabled homeowner under age 65 is eligible.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+        is_disabled: true
+        assessed_property_value: 8_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption_eligible: true
+
+- name: Case 3, blind homeowner under age 65 is eligible.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+        is_blind: true
+        assessed_property_value: 8_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption_eligible: true
+
+- name: Case 4, non-senior homeowner without disability or blindness is ineligible.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 64
+        assessed_property_value: 8_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption_eligible: false
+
+- name: Case 5, senior without assessed property is ineligible.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_exemption_eligible: false

policyengine_us/tests/policy/baseline/gov/states/sc/tax/property/homestead_exemption/sc_homestead_property_tax_reduction.yaml

@@ -0,0 +1,53 @@
+- name: Case 1, reduction equals the property tax on the exempt share of value.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+        assessed_property_value: 8_000
+        real_estate_taxes: 2_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_property_tax_reduction: 500
+
+- name: Case 2, reduction cannot exceed property taxes.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 65
+        assessed_property_value: 1_600
+        real_estate_taxes: 800
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_property_tax_reduction: 800
+
+- name: Case 3, ineligible filer gets no reduction.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 64
+        assessed_property_value: 8_000
+        real_estate_taxes: 2_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: SC
+  output:
+    sc_homestead_property_tax_reduction: 0

policyengine_us/variables/gov/states/sc/tax/property/homestead_exemption/sc_homestead_exemption.py

@@ -0,0 +1,19 @@
+from policyengine_us.model_api import *
+
+
+class sc_homestead_exemption(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "South Carolina homestead exemption"
+    unit = USD
+    definition_period = YEAR
+    reference = "https://dor.sc.gov/property/exempt-property"
+    defined_for = "sc_homestead_exemption_eligible"
+
+    def formula(tax_unit, period, parameters):
+        p = parameters(period).gov.states.sc.tax.property.homestead_exemption
+        assessed_exemption_amount = p.amount * p.assessment_rate
+        return min_(
+            add(tax_unit, period, ["assessed_property_value"]),
+            assessed_exemption_amount,
+        )

policyengine_us/variables/gov/states/sc/tax/property/homestead_exemption/sc_homestead_exemption_eligible.py

@@ -0,0 +1,22 @@
+from policyengine_us.model_api import *
+
+
+class sc_homestead_exemption_eligible(Variable):
+    value_type = bool
+    entity = TaxUnit
+    label = "Eligible for the South Carolina Homestead Exemption"
+    definition_period = YEAR
+    reference = "https://dor.sc.gov/property/exempt-property"
+    defined_for = StateCode.SC
+
+    def formula(tax_unit, period, parameters):
+        p = parameters(period).gov.states.sc.tax.property.homestead_exemption
+        person = tax_unit.members
+        head_or_spouse = person("is_tax_unit_head_or_spouse", period)
+        age = person("age", period.this_year)
+        is_disabled = person("is_disabled", period)
+        is_blind = person("is_blind", period)
+
+        return tax_unit.any(
+            ((age >= p.age_threshold) | is_disabled | is_blind) & head_or_spouse,
+        ) & (add(tax_unit, period, ["assessed_property_value"]) > 0)

policyengine_us/variables/gov/states/sc/tax/property/homestead_exemption/sc_homestead_property_tax_reduction.py

@@ -0,0 +1,17 @@
+from policyengine_us.model_api import *
+
+
+class sc_homestead_property_tax_reduction(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "South Carolina homestead property tax reduction"
+    unit = USD
+    definition_period = YEAR
+    reference = "https://dor.sc.gov/property/exempt-property"
+    defined_for = "sc_homestead_exemption_eligible"
+
+    def formula(tax_unit, period, parameters):
+        assessed_value = add(tax_unit, period, ["assessed_property_value"])
+        return add(tax_unit, period, ["real_estate_taxes"]) * (
+            tax_unit("sc_homestead_exemption", period) / max_(assessed_value, 1)
+        )