Opinion by Judge
GABRIEL.The Board of County Commissioners of Boulder County (County) appeals the Ruling and Order Regarding Motion for Summary Judgment and C.R.C.P. 106(a)(4) Review (Judgment) issued by the district court in favor of Hygiene Fire Protection District (District). We affirm.
I. Background
The District wanted to build a second fire station within its service area, which is located within Boulder County. To that end, the District approached the Boulder County Land Use Department (Land Use Department), which was in the process of reviewing the Blue Mountain Vista TDR/PUD (PUD), to request that the Land Use Department designate the land at issue here as the site for the station. The Land Use Department declined to do so, indicating that it preferred that the City of Longmont provide fire protection services to the proposed PUD and surrounding area.
After the PUD was approved, the District met again with the Land Use Department, this time to discuss the District’s plan to purchase the land, through agreement with the owners or condemnation, and to construct a fire station there. The District informed the Land Use Department that it believed the only approval process that it was required to complete was a Location and Extent Review, pursuant to section 30-28-110, C.R.S.2008. The Land Use Department, however, disagreed, maintaining that in addition to such Review, the District would need to submit the plan to a Special Use Review and to seek to amend the PUD, each pursuant to sections 3-202(A)(8) and 3-202(A)(9) of the Boulder Land Use Code.
Subsequently, the District submitted to the Land Use Department a completed application for Location and Extent Review. The Land Use Department, however, refused to accept the application for filing, reiterating that an amendment to the PUD was required. The District then filed a complaint *489with the district court, asking the court to find,- among other things, that the Land Use Department had exceeded its jurisdiction and abused its discretion in refusing to accept the application and in taking the position that the proposed project could not be completed absent an amendment to the PUD. The District further asked the court to declare that the fire station project could proceed and the land could be purchased.without amendment to the PUD.
The County moved to dismiss for failure to state a claim upon which relief can be granted and for failure to join indispensable parties, pursuant to C.R.C.P. 12(b)(5), 12(b)(6), and 19. As to the indispensable party motion, the County argued that if the only review required was the Location and Extent Review, then the interests of the owners of the land at issue would not be adequately protected, thus making them indispensable parties under C.R.C.P. 19.
The court rejected both of the County’s arguments and proceeded to the merits of the case. Thereafter, the District moved for summary judgment, and the court granted that motion. The court first found, as a matter of law, that the District, as a public entity, was not subject to zoning regulations. The court then determined that, because a PUD is considered a form of zoning, the District was not subject to the PUD regulations. The court thus issued a declaratory judgment that the District was not required to seek an amendment to the PUD in order to submit an application for Location and Extent Review. The County now appeals.
II. Joinder of Indispensable Parties
The County first argues that the trial court erred in finding that the owners of the land were not indispensable parties. We disagree.
We review a trial court’s denial of a motion to dismiss for failure to join indispensable parties for abuse of discretion. Board of County Comm’rs v. Roberts, 159 P.3d 800, 808 (Colo.App.2006) (citing Dunne v. Shenandoah Homeowners Ass’n, 12 P.3d 340, 344 (Colo.App.2000)). C.R.C.P. 19(a) states, in relevant part:
A person who is properly subject to service of process in the action shall be joined as a party in the action if: ... (2) he claims an interest relating to the subject of the action and is so situated that the disposition of the action in his absence may: (A) [a]s a practical matter impair or impede his ability to protect that interest....
“Mere interest in the subject matter of litigation, even if the interest is substantial, is insufficient to make a party indispensable.” Roberts, 159 P.3d at 807. “If the interests of the parties before the court may be finally adjudicated without adversely affecting the rights of an absent person, the absent party need not be joined.” Id. at 808.
Here, the relief that the District sought in its complaint was narrow. The District asked the court to find, among other things, that the Land Use Department had exceeded its jurisdiction and abused its discretion in refusing to accept the District’s application and in taking the position that the proposed project could not be completed absent an amendment to the PUD. A finding that the Land Use Department abused its discretion by refusing to perform the ministerial task of accepting the District’s application in no way implicated the landowners’ interests so as to make them indispensable parties. Nor did the District’s request for a declaration that the project could proceed absent amendment to the PUD. At root, the question presented involved which process the District was required to employ in order to build its fire station. This determination did not impair the landowners’ ability to protect their interests because, whether the court required a Location and Extent Review, as the District sought, or an amendment to the PUD, which the County believed to be required, the landowners would have had the opportunity to be heard and protect their interests through the applicable statutory processes. See, e.g., § 24-67-106(3), C.R.S.2008 (requiring public hearing); §§ 38-1-101 to -122, C.R.S.2008 (procedures for eminent domain); Blue River Defense Comm. v. Town of Silverthome, 33 Colo.App. 10, 14, 516 P.2d 452, 454 (1973) (even though certain entities had right to overrule county’s decision under Planning Act, county resi*490dents were entitled to an opportunity to present their objections and views as part of the planning commission’s approval process).
Accordingly, the trial court did not abuse its discretion by denying the County’s motion to dismiss for failure to join the landowners as indispensable parties.
III. Amendment of PUD
The County next contends, based on its interpretation of the Planned Unit Development Act of 1972, §§ 24-67-101 to -108, C.R.S.2008 (PUD Act), that the trial court erred in finding that the District did not have to amend the PUD to allow it to build a new fire station. Again, we are not persuaded.
We review the grant of summary judgment de novo. Aspen Wilderness Workshop, Inc. v. Colorado Water Conservation Bd., 901 P.2d 1251, 1256 (Colo.1995). In interpreting statutory language, we must strive to give effect to the intent of the legislature. Romanoff v. State Comm’n on Judicial Performance, 126 P.3d 182, 188 (Colo.2006). “In doing so, our starting point is the plain meaning of the language used.” Id. We should read the statute in such a way as to give effect to every word. Id. “We also must consider the language in the context of the statute as a whole.” Id. We must “give effect to the ordinary meaning of the language and read the provisions as a whole, construing each consistently and in harmony with the overall statutory design, if possible.” People v. Cross, 127 P.3d 71, 74 (Colo.2006). Interpretations that will render words or phrases superfluous should be rejected. Id. at 73. Only if a statute is reasonably susceptible of more than one meaning may we look to other sources to aid in our interpretation. Romanoff, 126 P.3d at 188.
This case requires us to examine the interplay between the PUD Act and the so-called Planning Act, §§ 30-28-101 to -139, C.R.S. 2008. The District claims that approval of its new fire station required only that it comply with the Planning Act. Under that Act, the District would submit “the proposed location and extent” of the planned fire station to the Land Use Department for approval. § 30-28-110(l)(a), C.R.S.2008. If the Land Use Department were to disapprove the proposal, however, the District could overrule that Department by a majority vote of its governing board. § 30-28-110(l)(c), C.R.S.2008.
The County, on the other hand, claims that the District was required to comply with the requirements of the PUD Act. Under the PUD Act, a change in use of a parcel of land like that proposed by the District would be considered-a modification of the PUD. § 24-67-106, C.R.S.2008. No such modification could be made, however, without first holding a public hearing in the manner designated by the County. §§ 24-67-104, 24-67-106(3)(b), C.R.S.2008. Moreover, pursuant to the PUD Act, the County has enacted certain provisions of the Boulder Land Use Code regarding the amendment of a previously approved PUD. Boulder County Land Use Code §§ 3-202(A)(9), 6-1100. The County contends that the District would also be required to amend the PUD pursuant to these provisions.
The trial court found that the District was required to comply solely with the Planning Act. We agree with the trial court.
Courts have long held that public entities “have the power to overrule or disregard the restrictions of county or municipal
zoning regulations.” Reber v. S. Lakewood Sanitation Dist., 147 Colo. 70, 75, 362 P.2d 877, 880 (1961). Section 30-28-110(1)(b), C.R.S.2008, of the Planning Act codifies this rule, exempting a county’s own facilities and operations from the county land use planning process. See also Cottonwood Farms v. Bd. of County Comm’rs, 725 P.2d 57, 59 (Colo.App.1986), aff'd, 763 P.2d 551 (Colo.1988). This exemption also applies to public facilities authorized or financed by public officials or entities falling outside the province of the county, including special districts like the District here. § 30-28-110(1)(c); see also Reber, 147 Colo, at 75, 362 P.2d at 879-80 (holding, under predecessor to section 30-28-110(l)(e), that sanitation district had the right to overrule county planning commission’s disapproval of proposed sewage disposal plant, and noting that numerous courts have recognized that districts, authorities, and other state-authorized subdivisions have such authority even in the absence of definite statutory direction). Nowhere does the *491Planning Act indicate that it applies only in the context of zoning decisions.
The PUD Act was enacted after the Planning Act and was added to the same chapter of the 1963 Colorado Revised Statutes, only four articles after the Planning Act. See Ch. 82, sec. 1, §§ 106-6-1 to -8, 1972 Colo. Sess. Laws 508-13; §§ 106-2-1 to -38, C.R.S.1963. Yet, nothing in the PUD Act suggests that it was intended to alter the broad exemption given to public entities in the Planning Act. To the contrary, a close reading of the language of the PUD Act supports the notion that public entities are exempt.
Section 24 — 67—106(3)(b), on the one hand, requires a party wishing to make a substantial change in use to a portion of a PUD to participate in the County review and amendment process discussed above. Nothing in this section states that it applies to public entities. Section 24 — 67—106(3)(b.5), C.R.S. 2008, on the other hand, expressly applies to public entities and sets forth the procedures to be followed when public entities holding legal title to land already set aside in a PUD for governmental uses wish to subdivide the land, release it from usage restrictions, or sell or dispose of it.
Notably, there is no analog to section 24-67 — 106(3)(b.5) governing situations in which land in a PUD is to be changed to a public use. Moreover, section 24-67-106(3)(b.5) requires the county to make certain findings regarding the change in land use, including a finding that the use of the land shall “be consistent with the efficient development and preservation of the entire planned unit development and with the plan.” § 24-67-106(3)(b.5)(II), C.R.S.2008. The county must make the same finding, however, in considering an application under section 24-67-106(3)(b). Accordingly, if section, 24-67-106(3)(b) were interpreted to apply to public entities, as the County contends, then the identical language in section 24-67-106(3)(b.5) would be superfluous. Accordingly, the language of the PUD Act demonstrates that public entities are exempt, except where the General Assembly has chosen to include them expressly.
The language and legislative history of the Planning Act likewise suggest a legislative intent to maintain the exemptions afforded public entities even after the enactment of the PUD Act. Section 30-28-110(l)(a) of the Planning Act is implicated whenever a master plan has been adopted. That Act, in turn, requires the adoption of a master plan whenever any sort of physical development is to be undertaken in an unincorporated portion of the county. § 30-28-106(1), C.R.S. 2008.
In 2007, twenty-five years after the PUD Act was in place, the Planning Act was amended to revise section 30-28-106(3)(a), C.R.S.2008. Ch. 165, sec. 1, § 30-28-106, 2007 Colo. Sess. Laws 612. Additional language was added to that section specifying that a master plan is considered advisory and is intended to guide land development decisions, until such time as it is included in the county’s or region’s “subdivision, zoning, platting, planned unit development, or other similar land development regulations,” at which point it may be made binding. Id. (emphasis added). Thus, the Act specifically envisions the existence of PUDs. Nonetheless, the Act does not indicate that the exemptions granted to the public entities elsewhere in the Act do not apply in the context of a PUD.
In essence, the County asks us to conclude that the PUD Act should be interpreted to supersede the exemption from the county planning process long afforded public entities under the Planning Act and, prior to the enactment of that statute, at common law. We perceive nothing in the language of the statutes and have found no legislative history or other authority to suggest that the General Assembly intended to effectuate so dramatic a change in the existing law, particularly where, as here, that change would be implied, not express. As noted above, the provisions of the PUD Act on which the County relies are general in their terms and do not expressly reference public entities. See § 24-67-106(3)(b). The Planning Act, in contrast, does expressly reference public entities and authorizes them to overrule county planning decisions. § 30-28-110(l)(c). “[B]e-fore a later statute of general terms is deemed to revoke an existing provision of a statute which is specific in its terms, there *492must be a clear and unmistakable intent to do so.” City of Colorado Springs v. Board of County Comm’rs, 895 P.2d 1105, 1118 (Colo.App.1994). We perceive no such clear and unmistakable intent here. To the contrary, for the reasons noted above, the language of both the Planning Act and the PUD Act persuades us that the General Assembly did not intend to alter the broad exemption for public entities, except in those circumstances in which the Act expressly so provides. See, e.g., § 24-67-106(3)(b.5).
The cases cited by the County concerning the requirements of the Land Use Act, §§ 24-65.1-101 to -502, C.R.S.2008, do not suggest otherwise. Indeed, if anything, these cases support the District’s position here. In both City & County of Denver v. Board of County Commissioners, 782 P.2d 753, 766 (Colo.1989), and City of Colorado Springs v. Board of County Commissioners, 895 P.2d at 1118, the courts concluded that public entities were subject to the procedures of the Land Use Act and county regulations that were adopted pursuant thereto. In the Land Use Act, however, the General Assembly had expressly authorized counties to regulate certain public entities under specified conditions. See, e.g., §§ 24-65.1-201 to -204, C.R.S.2008. Thus, these cases do not undermine the principle that public entities are exempt from zoning or other planning and development regulations. Rather, they demonstrate that for such planning regulations to apply to public entities notwithstanding section 30 — 28—110(l)(c) of the Planning Act, there must be express direction from the legislature to that effect. City & County of Denver, 782 P.2d at 766; City of Colorado Springs, 895 P.2d at 1118.
Finally, we note that our conclusion is fully consistent with the purposes of both the Planning Act and the PUD Act. On its face, the Planning Act gives substantial authority to public entities to act for the public good. See § 30-28-110, C.R.S.2008. Thus, public entities are required only to go through the Location and Extent Review process, which is not conclusively binding on them. § 30-28-110(1)(c); see also Blue River Defense Comm., 33 Colo.App. at 14, 516 P.2d at 454. Such a process provides maximum flexibility.
The purpose of the PUD Act, on the other hand, is to allow “the flexibility necessary to permit adjustment to changing needs.” Tri-State Generation & Transmission Co. v. City of Thornton, 647 P.2d 670, 677-78 (Colo.1982). This adaptability was a response to the perception that traditional zoning was overly rigid. Id. at 677.
Requiring public entities to comply with the stricter rules of the PUD Act when attempting to serve the public interest, as the County asks us to do here, would undermine the purposes of the Planning Act and would serve none of the purposes of the PUD Act. We have seen nothing to suggest that the General Assembly intended such a result.
For these reasons, we conclude that the District was required to complete only a Location and Extent Review under the Planning Act and was not required to seek an amendment of the PUD under the PUD Act or to comply with the County’s related subdivision regulations.
The Judgment is therefore affirmed.
Judge VOGT concurs. Judge RUSSEL dissents.