OPINION
¶ 1 Appellants Steven and Jeanette Wash-burn, the Southern Arizona Homebuilders Association (SAHBA), and Washburn Company, Inc. (collectively the Washburns), appeal from the trial court’s order granting summary judgment in favor of appellee Pima County. The Washburns contend on appeal that the county lacked statutory authority to adopt an ordinance requiring builders of single-family homes to incorporate design features allowing for greater wheelchair access and that the ordinance violates the Arizona Constitution. We affirm.
Background
¶2 On appeal from a grant of summary judgment, we view the facts and all reasonable inferences in the light most favorable to the party opposing the motion.
Pleak v. Entrada Property Owners’ Ass’n,
¶ 3 The Washburns applied for a permit to build a single-family home, but the proposed design failed to comply with the ordinance, and the county denied the application. They later filed a declaratory judgment and special action complaint in which they asked the trial court to declare that the county lacked statutory authority to adopt the ordinance and that it violated both the Equal Protection and Privacy Clauses of the Arizona Constitution. Ariz. Const, art. II, §§ 8, 13. The trial court granted the Washburns’ request for resolution of the special action complaint by an order to show cause (OSC) hearing pursuant to Rule 4(c), Ariz. R.P. Special Actions, 17B A.R.S. The county filed a motion for summary judgment and objected to resolving the complaint by OSC. Following arguments on the OSC, the trial court issued an under-advisement ruling, essentially granting summary judgment in favor of the county. In so ruling, the court concluded that the resolution of another case in which SAHBA had participated barred the Washburns from challenging the county’s statutory authority to adopt the ordinance. The court also found that the ordinance was constitutional. Because it is clear from the record that the trial court denied the Washburns’ request for declaratory relief, we need not determine whether the trial court erred in accepting jurisdiction of their special action complaint, an argument the county raised only in its motion for summary judgment. See Ariz. R.P. Special Actions 1(a) (“Except as authorized by statute, the special action shall not be available where there is an equally plain, speedy, and adequate remedy by appeal____”). Our review focuses instead on whether the trial court properly granted summary judgment in the county’s favor.
Standard of Review
¶ 4 Summary judgment is proper if the evidence presented by the party opposing the motion has so little probative value, given the required burden of proof, that reasonable jurors could not agree with the opposing party’s conclusions. Ariz. R. Civ. P. 56(c)(1), 16 A.R.S., Pt. 2;
Orme Sch. v. Reeves,
Preclusion
¶ 5 The Washburns first contend the trial court erred in determining either
res judicata
or collateral estoppel precluded them from asserting their statutory claims. These doctrines, also referred to as claim and issue preclusion, preclude a party from relitigating a claim or an issue as a result of previous litigation.
See Smith v. CIGNA HealthPlan of Ariz.,
¶ 6 Relying on
Chicot County Drainage District v. Baxter State Bank,
¶ 7 Unlike in
Chicot County Drainage District,
however, the district court in the federal case ruled that it lacked subject matter jurisdiction over the merits of that case. Although SAHBA could have challenged that ruling on direct appeal, it instead filed this action. Citing
Wages v. Internal Revenue Service,
Statutory Interpretation
¶8 The legislature authorized counties to adopt building codes but “limited [that authority] to the [adoption of] ... [a]ny building, electrical or mechanical code that has been promulgated by any national organization or association that is organized and conducted for the purpose of developing codes.” A.R.S. § 11-861(A), (C)(1). The Washburns challenge the county’s adoption of the ANSI standards, which, through mandatory language, set forth a comprehensive collection of
rules for
builders
to
facilitate building access to people confined to wheelchairs. The Washburns contend that the county could not adopt the ANSI standards under § 11-861 because ICC neither titled nor classified those standards as a “code.” Whether the legislature authorized the county to adopt requirements like the ANSI standards is a question of law subject to our
de novo
review.
See Hohokam Irrigation and Drainage Dist. v. Ariz. Pub. Serv. Co.,
¶ 9 The principal goal in interpreting a statute is to ascertain and give effect to the legislature’s intent.
Pleak,
¶ 10 “Statutes relating to the same subject matter should be read
in pari materia
to determine legislative intent and to maintain harmony.”
Goulder v. Ariz. Dep’t of Transp. Motor Vehicle Div.,
a published compilation of rules or regulations prepared by a technical trade association and includes any building code, electrical wiring code, health or sanitation code, fire prevention code, inflammable liquids code, code for slaughtering, processing and selling meat and meat products or for production, pasteurizing and sale of *576 milk and milk products, or other code which embraces rules and regulations pertinent to a subject which is a proper subject of municipal legislation.
A.R.S. § 9-801(1). The Washburns point to the broad function-based language the legislature used to define adoptable codes in this section relating to municipalities, contrast it with the lack of any specific definition for “code” in the section relating to counties, and argue that the difference demonstrates the legislature’s intent to provide counties with markedly less discretion in crafting an appropriate building code. Specifically, the Wash-burns note that cities are authorized to adopt any “published compilation of rules or regulations prepared by a technical trade association,” § 9-801(1), but argue that counties may only adopt guidelines that are specifically characterized by national technical organizations as “codes.”
¶ 11 We presume the legislature is aware of existing statutes when it enacts new statutes, and we presume the legislature intends to change the law when it substantively changes the language of a statute.
Prudential v. Estate of Rojo-Pacheco,
¶ 12 In
Rotter v. Coconino County,
¶ 13 Like the statute addressed in
Rotter,
§ 11-861 entitles counties to determine and implement policies intended to further the general health, safety, and welfare of their residents.
See Village of Euclid v. Ambler Realty Co.,
¶ 14 Just as the appellants in Rotter asked the supreme court to draw far-reaching conclusions from the legislature’s inclusion of one clause in a city enabling statute and its omission from a comparable county enabling statute, the Washburns ask this court to draw a similar far-reaching conclusion from the legislature’s failure to elaborate on the definition of the word “code” in § 11-861(C)(1) when it had done so in the comparable statute relating to municipalities. Following the supreme court’s example in Rotter, we decline to assume any legislative intent from the mere omission of surplus explanatory language in the statute relating to counties when the two statutes in question have such obviously similar goals.
¶ 15 Nor does our function-based reading of the word “code” render superfluous the second mechanism by which a county may
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adopt a building code.
See State v. McKeon,
¶ 16 In contrast to the Washburns’ suggestion that we should view the “largest city” clause from § 11-861(0(1) as an implied limitation on the definition of the word “code,” the clause shows that when the legislature has intended to constrain a county’s authority to adopt building codes, it has been able to articulate the nuances of such limitations. The clause requires a county that has adopted its building code from the “largest city” in the county to also adopt any subsequent building code changes the city enacts. The legislature has also limited a county’s ability to adopt fire codes by mandating that such codes must be at least as stringent as the fire code adopted by the state fire safety committee. See § 11 — 861 (C) (2); A.R.S. § 41-2146. 1 Given the willingness of the legislature to lucidly articulate specific limitations on county authority in the context of adopting building requirements, we will not infer from its silence an intent to limit counties to the most narrow and hypertechnical definition of the term “code.”
¶ 17 The Washburns also asserted in oral argument before this court that the legislature’s use of the word “limited” in § 11-861(C) conveys its intent to narrow the definition of the word “code” used in the sentence thereafter. Viewed in context, the obvious thrust of that provision confines counties to the use of building standards “promulgated by any national organization or association that is organized and conducted for the purpose of developing codes.” 2 In short, § 11-861(0 limits counties’ choice of building regulations to those that have been developed by knowledgeable professionals — but does not limit the definition of the word “code.” To the contrary, § 11-861(C) explicitly authorizes a county to adopt “[a]ny building, electrical or mechanical code” which has the appropriate professional pedigree. (Emphasis added.) Thus, the Washburns’ assertion that § 11-861(C) impliedly instructs us to construe the word “code” as a highly technical term of art — rather than by its common usage— finds little support in the language of the statute itself.
¶ 18 The Washburns also assert that, because § 11-861 requires counties to adopt building “codes” promulgated by nationally recognized organizations, we should interpret
*578
the term consistently with the term’s meaning within the construction industry. However, we attribute no specialized meaning to statutory language unless the legislature has clearly conveyed its intent that we do so.
Kilpatrick v. Superior Court,
¶ 19 Nor do we find any caveat in the ANSI standards themselves indicating they could not constitute a “code” within the meaning of § 11-861(C)(1). The foreword to the ANSI standards provides in part that the standards, “when adopted as a part of a building code, would be compatible with the building code and its enforcement.” According to the Washburns, this language demonstrates that the ANSI standards were not intended to stand by themselves as a “code.” But the Washburns’ argument presupposes that a county could never amend or augment its current building code in a minor fashion without adopting a new comprehensive building code. We find nothing in § 11-861(C)(1) that prevents the county from amending or augmenting its comprehensive building regulations with self-contained “codes,” promulgated by appropriate national organizations, that address discrete components of home construction. Moreover, the above-quoted foreword to the ANSI standards demonstrates ANSI’s expectation that the standards would have an equal status to other parts of a pre-existing building code once adopted.
¶ 20 We are also not persuaded to reach a contrary result merely because initially the ANSI standards were not applicable to single-family homes. See ANSI standards § 101 (“These criteria are intended to be consistent with the intent of only the technical requirements of the Federal Fair Housing Act Accessibility Guidelines.”); 42 U.S.C. § 3603(b)(1) (Fair Housing Act does not apply to most single-family homes). Notwithstanding the original application of the ANSI standards, those standards include a provision that suggests ANSI drafted the standards to be capable of flexible application to different types of “dwelling units” in various settings. Furthermore, the foreword demonstrates that ANSI anticipated the need to be compatible with other types of building codes and drafted the standards with this in mind. Indeed, the very use of the term “standard” connotes compatibility with complementary regulations. We address the Washburns’ other claims regarding the county’s application of the ANSI standards to single-family homes in the context of their challenges to the ordinance’s constitutionality.
¶ 21 We also find no policy-based explanation for why the legislature would have intended to limit the breadth of the word “code” as used in § 11-861(0(1). Without question, counties are generally empowered to regulate the construction of homes consistent with specifications suggested by appropriate national bodies. A county’s ability to do so depends upon its power to mandate the incorporation of particular design elements. The Washburns do not dispute that counties may enact guidelines regulating the construction of new homes. 3 Although they strenu *579 ously argue that a county may only adopt a set of requirements labeled as a “code” but not a set of requirements labeled as “standards,” they point to no procedural differences or differences in professional or scientific scrutiny between the manner in which ANSI promulgated the standards adopted here and the manner in which, for example, the ICC promulgates the International Building Code. Both publications define minimum design criteria to implement public policy goals in the building of structures; both anticipate that local governmental authorities will tailor the criteria to promote regionally prioritized public policy; and, once adopted, both contain mandatory language for how the construction must occur. Thus, we are given no plausible explanation as to why the legislature would have intended to make the hypertechnical distinction that the Washburns now urge in challenging the county’s authority to adopt the ANSI standards as a code. To accept the Washburns’ construction of § 11-861(0 would require us to exalt form over substance. For the foregoing reasons, we find that the county has not exceeded its statutory authority in adopting the ANSI standards here because those collected standards constitute an example of “[a]ny building ... code that has been promulgated by any national organization ... that is organized for the purpose of developing codes.” § 11-861(0(1).
¶ 22 In a related argument, the Washburns also assert the county lacked the authority to adopt only portions of the ANSI standards. But they cite no authority for this proposition, and we defer to the determination of the Board of Supervisor that the community’s interests were advanced by adopting only specific portions of the ANSI standards.
See Ariz. Fence Contractors Ass’n v. City of Phoenix,
Constitutional Claims
¶23 As they did below, the Wash-burns next claim the ordinance violates a homeowner’s right to privacy in his or her home under the Privacy Clause, article II, § 8 of the Arizona Constitution. Although they concede that the government possesses the right to adopt building, fire, and mechanical codes that provide for the protection of the general population, they question whether the county can constitutionally impose costly design requirements on all new private homeowners “that have value to less than 1% of the population.” They further assert the ordinance “deprives new homeowners and builders of the fundamental right to design private homes ... by imposing design criteria that invade the exercise of personal, private, and aesthetic choices for personal private living spaces.”
¶24 Homeowners do not have “a right to be completely free from governmental regulation of the use and occupancy of [their] real property.”
State v. Watson,
¶ 25 In a related argument, the Washburns contend the ordinance violates their rights under Arizona’s Equal Protection Clause, article II, § 13 of the Arizona Consti
*580
tution, because it burdens only those people constructing new homes. The level of scrutiny we apply to a discriminatory law depends upon whether that law affects a fundamental right or a suspect class or enacts a gender-based classification.
Simat Corp. v. Ariz. Health Care Cost Containment Sys.,
¶26 To the extent the Washburns argue the Board of Supervisors had no rational basis for concluding that private home designs should facilitate access to people confined to wheelchairs, we disagree. “[I]f the court can hypothesize any rational reason why the legislative body made the choice it did, the statute or ordinance is constitutionally valid. This test validates statutes even if the legislative body did not consider the reasons articulated by the court.”
Haines v. City of Phoenix,
¶ 27 The uncontested evidence established that approximately one percent of the population is confined to wheelchairs, but the county points out that a much larger percentage will suffer a disability at some point in their lives. Although all age groups are affected by disability, the county introduced evidence that approximately forty-one percent of people over the age of sixty-five have some form of disability. Disability is a growing problem both nationally and locally, and the county also introduced evidence that Arizona’s population of people over the age of sixty is expected to triple by 2025. Although many of these disabled people will not be confined to wheelchairs, the county concluded from these figures that the number of people confined to wheelchairs is rising. For these reasons, the county addressed a legitimate governmental interest when it adopted a building code designed to increase the number of homes accessible to those in wheelchairs.
Cf. Arizona Fence Contractors Ass’n,
¶ 28 The Washburns also argue that the ordinance is not rationally related to further the county’s interests. Again, we disagree. “A perfect fit is not required; a statute that has a rational basis will not be overturned ‘merely because it is not made with “mathematical nicety, or because in practice it results in some inequality.” ’ ”
Big D Constr. Corp. v. Court of Appeals,
¶29 The Washburns lastly contend the ordinance does not rationally advance the county’s interests because it places the financial design burdens on homeowners who will probably never be confined to wheelchairs. But the county submitted to the trial court the results of a study suggesting that complying with the ordinance would cost only about $100. In addition, § 103.1 of the ordi
*581
nance provides that the county may waive any design requirement if a building official determines that the cost of complying with the requirement exceeds $200. Indeed, the Board of Supervisors found that the cost of including the ordinance’s designs into a new home was substantially less than the cost of renovating a home to accommodate a person confined to a wheelchair. On this record, the Board of Supervisors could have rationally concluded that the benefit to the community in providing for the disabled justified the comparatively minimal cost of implementing the required design features. Although the Washburns now contest the accuracy of the county’s assertions as to the costs of these renovations, they failed in the trial court to introduce controverting evidence regarding the cost of compliance.
See
Ariz. R. Civ. P. 56(e), 16 A.R.S., Pt. 2. The Washburns, therefore, have failed to establish that there were genuine issues of material fact precluding summary judgment.
See Orme Sch.,
¶ 30 Affirmed.
Notes
. The underlying policy of these provisions-promoting a minimum measure of uniformity between adjacent jurisdictions-is inapplicable here.
. The Washburns do not dispute that ANSI is a “national organization or association” organized for the purpose of developing and promulgating regulations for the construction of homes. Thus, they do not challenge the professional pedigree of ANSI in this regard. Rather, they argue that ANSI promulgates “standards" rather than codes. Their challenge to ANSI as a qualified organization under § 11 — 861(A) and (C)(1) thus depends on a broader question we address here-whether the legislature intended the word "code” to include comprehensive sets of standards such as those promulgated by ANSI.
. During oral argument, the Washburns presented us with an example of a "code” that, in their view, a county would be authorized to adopt, "the 2000 International Residential Code."
