MR. JUSTICE HASWELL

delivered the opinion of the Court.

Defendants appeal from a writ of mandate issued by the district court, Gallatin County, Hon. W. W. Lessley, district judge, ordering them (1) to lift sanitary restrictions and record a certificate of survey on certain property within the City of Bozeman, and (2) assessing $750 attorney fees plus costs against the State Department of Community Affairs.

Relator is Charles R. Swart, a licensed and registered land surveyor. The three defendants are Edward W. Casne, chief of the Subdivision Bureau of the Environmental Sciences Division of the Montana Department of Health and Environmental Sciences (MDH); Carl Stucky, the clerk and recorder of Gallatin County; and the Department of Community Affairs of the State of Montana (DCA).

The subject property is a parcel of land containing 9,361 square feet located in Block 50, Northern Pacific Addition to the City of Bozeman, Gallatin County, Montana. The original plot was recorded many years ago and shows 24 lots in Block 50. The subject property consists of five lots numbered 13, 14, 15, 16, and 17, located in the southwest corner of Block 50. A house which is connected to city water and sewage facilities is located on the subject property.

Relator surveyed the five lots and prepared a certificate of survey showing a straight line dividing each lot into substantially equal parts. The owner attached a certificate of exemption from the requirements of the Montana Subdivision and Platting Act as an “occasional sale” pursuant to section 1 l-3862(6)(d), R.C.M. *304 1947. Apparently the owner wants to sell the east half of the five lots comprising a square shaped parcel.

The certificate of survey was presented to defendant Casne who refused to remove the sanitary restrictions on the subject property because two administrative regulations of DCA provided, in effect, that any resubdivision or redesign of a recorded subdivision plat had to be filed as an amended plat after review and approval of local authorities. MAC 22-2.4B(6) — S420(4)(a), Procedural Requirements for Local Regulations and MAC 22-2.4B(30) — S4090(3)(a), Uniform Standards for Certificates of Survey.

Thereafter the Gallatin County clerk and recorder refused to accept for filing the certificate of survey because he believed that under the foregoing DCA regulations and under Gallatin County subdivision regulations an amended plat was required and the sanitary restrictions had not been lifted.

Relator then filed the present action seeking a writ of mandate to compel the lifting of sanitary restrictions, the filing of the certificate of survey, and payment of his attorney fees and costs in the action. The case was submitted to the district court on the basis of a stipulation of facts and an evidentiary hearing. The district court entered findings of fact, conclusions of law, and a writ of mandate granting relator the requested relief.

Among other things, the district court made findings of fact that no genuine problems existed relating to water availability, sewage disposal, solid waste disposal, or other environmental factors, and that the refusal to lift sanitary restrictions and file the certificate of survey was not based on any such factors. The essence of the district court’s conclusions of law was that the certificate of survey qualified as an “occasional sale” under the Subdivision and Platting Act and was accordingly exempt from the surveying and platting requirements for subdivisions (Sec. 1 l-3862(6)(d), R.C.M.1947); that the two administrative regulations of DCA, Gallatin County subdivision regulations, and the City of Bozeman subdivision regulations, were in conflict with *305 the statute and void; that there was a clear legal duty to lift the sanitary restrictions and file the certificate of survey; that a writ of mandate was a proper remedy; and that attorney fees of $750 and costs should be awarded relator against DCA.

All defendants appeal from the judgment.

We summarize the issues for review in this manner:

(1) Are the administrative regulations of DCA void?

(2) Is a writ of mandate a proper remedy?

(3) Should attorney fees be awárded?

The substance of defendants’ argument on the first issue is that the DCA regulations simply implemented the Subdivision and Platting Act; were within the rule-making authority delegated to it by the legislature; and the DCA regulations were not in conflict with the Subdivision and Platting Act. They view MAC 22-2.4B(6) — S420(4)(a) and MAC 22-2.4B(30)-S4090(3) (a) as providing standards by which local authorities can determine whether the “occasional sale” exemption in the Subdivision and Platting Act in fact constitutes an evasion of its requirements. They argue that the DCA administrative regulations carry out the broad objectives of the Subdivision and Platting Act and that absent these regulations, two conflicting sets of boundary records and haphazard land development would result. They further contend that the DCA regulations do not conflict with the Subdivision and Platting Act; that the district court’s finding that they do conflict ignores established rules of statutory construction; and that the district court’s implied finding that the “occasional sale” exemption applies to resubdivision and redesign of lots in recorded plats is error.

Section 11-3862(6), R.C.M.1947, of the Subdivision and Platting Act provides the “occasional sale” exemption:

“(6) Unless the method of disposition is adopted for the purpose of evading this act, the following divisions of land are not subdivisions under this act but are subject to the surveying requirements of this section for divisions of land not amounting to subdivisions.

*306 “(d) A single division of a parcel when the transaction is an occasional sale.”

Section 11-3861(13), R.C.M.1947, of the Subdivision and Platting Act defines an “occasional sale”:

“As used in this act, unless the context or subject matter clearly requires otherwise, the following words or phrases shall have the following meanings:

“(13) ‘Occasional sale’ means one sale of a division of land within any twelve (12) month period.”

Section 11-3861(12), R.C.M.1947, of the Subdivision and Platting Act provides that “any resubdivision” is a subdivision within the meaning of the act.

These statutes are clear and unambiguous. They plainly provide that although a resubdivision or redesign of an existing subdivision constitutes a subdivision under the act, an “occasional sale” is exempt from the requirements applicable to subdivisions, i. e., the preparation of an amended plat with review and approval of local authorities, and the filing of an amended plat instead of a certificate of survey. Where the language of a statute is plain, unambiguous, direct and certain the statute speaks for itself and there is nothing left for the court to construe. Keller v. Smith, 170 Mont. 399, 553 P.2d 1002; Dunphy v. Anaconda Co., 151 Mont. 76, 438 P.2d 660, and cases cited therein. Our function is simply to declare what in terms or substance is contained in the statute, and neither insert what has been omitted nor omit what has been inserted. Section 93-401-15, R.C.M.1947; Clark v. Hensel Phelps Construction Co., . . . Mont. . . ., 560 P.2d 515, 34 St.Rep. 61; Hammill v. Young, 168 Mont. 81, 540 P.2d 971.

Defendants argue, however, that such construction of the pertinent provisions of the Subdivision and Platting Act conflict with many recognized principles of statutory construction including the rule that a particular provision of a statute controls over a *307 general provision (section 93-401-16, R.C.M.1947; City of Billings v. Smith, 158 Mont. 197, 490 P.2d 221); that legislative intent must be determined by a consideration of .the act as a whole (State ex rel. Jones v. Giles, 168 Mont. 130, 541 P.2d 355; State ex rel. Cashmore v. Anderson, 160 Mont. 175, 500 P.2d 921, cert. denied Burger v. Anderson, 410 U.S. 931, 93 S.Ct. 1372, 35 L.Ed.2d 593; Sutherland, Statutory Construction, 4th Ed., Vol. 2A, Sec. 46.05, p. 56); that in construing a statute, the court should, where possible, adopt a construction which will give effect to all provisions (section 93-401-15, R.C.M.1947; State Board of Equal. v. Cole, 122 Mont. 9, 195 P.2d 989); and that statutes should be construed to produce a reasonable result (section 49-134, R.C.M.1947; Keller v. Smith, supra; Sutherland, Statutory Construction, 4th Ed., Vol. 2A, Sec. 46.05, p. 56).

The short answer to this contention is that these rules of statutory construction apply to cases involving conflicting or ambiguous provisions of a statute where the court is required to construe and interpret the meaning of a statute. They have no application where, as here, the language of the statute is clear and unambiguous. In the latter case, courts cannot go beyond the language of the statute and apply extrinsic rules of construction but must declare what the statute plainly states. Keller v. Smith, supra; Dunphy v. Anaconda, supra.

The two DCA regulations in question are identical. They were promulgated and adopted by DCA as part of the Montana Administrative Code, MAC 22-2.4B(6) — S420(4)(a) and MAC 22-2.4B(30) — S4090(3)(a). They provide:

“Procedures for divisions of land exempted from public review as subdivisions — use of exemptions for the purpose of evading the act. Unless the method of disposition is adopted for the purpose of evading the Montana Subdivision and Platting Act, divisions of land meeting the criteria set out in section 11-3862(6), R.C.M.1947, are not subdivisions subject to review under the Act. To assure that the method of disposition is not used to evade the act the following requirements must be met in the use of exemptions.

*308 “(a) The exemptions contained in section 11-3862(6), R.C.M. 1947, do not apply to the resubdivision or redesign of subdivisions platted and filed with the clerk and recorder. Any such resubdivision or redesign must be reviewed and approved by the governing body and an approved amended plat thereof must be filed with the clerk and recorder.”

These regulations are in direct conflict with the provisions of the Subdivision and Platting Act heretofore set forth in section 11-3862. They eliminate the statutory exemption as applied to “resubdivisions or redesign” of platted and recorded subdivisions. They require an amended plat reviewed and approved by the governing body to be filed with the clerk and recorder in direct contradiction to the statutory exemption. They engraft additional .and contradictory requirements on the statute in the guise of defining and implementing the evasion of statutory requirements. They frustrate the purpose of the “occasional sale” exemption of the Act. As such, the DCA regulations are void on their fact. See Bartels v. Miles City, 145 Mont. 116, 399 P.2d 768. It is axiomatic that a statute cannot be changed by administrative regulation. See Begay v. Graham, 18 Ariz.App. 336, 501 P.2d 964.

Defendants further contend that the DCA regulations are clearly within the powers delegated to DCA by the legislature, and cite section 11-3863(2), R.C.M.1947, providing that DCA has authority to prescribe reasonable minimum requirements for subdivision regulations under the Subdivision and Platting Act which shall include detailed criteria for the content of the environmental assessment required by the Act and shall provide for review of preliminary plats.

This grant of authority does not include the right to promulgate regulations in direct conflict with the Act. Where, as here, the Act provides for exemption of occasional sales from the subdivision requirements, DCA cannot prescribe subdivision regulations eliminating the exemption for the reasons heretofore stated. An administrative agency is not a “super legislature” *309 empowered to change statutory law under the cloak of an assumed delegated power.

Defendants next contend that a writ of mandate is not a proper remedy in this case. They argue that there is no clear legal duty to lift the sanitary restrictions or file the certificate of survey. They point out that the thrust of relator’s complaint is that the DCA regulations are invalid which requires a declaratory judgment action rather than extraordinary relief by writ of mandate.

While MDH has the statutory authority under section 69-5003(3) to review a certificate of survey regarding sanitary restrictions, this provides no justification either for the MDH or the clerk and recorder to refuse to process relator’s certificate of survey. MDH’s authority to review a certificate of survey under section 69-5001, et seq., R.C.M.1947, relates to sewage disposal, water quality and availability, solid waste disposal and other environmental factors such as recreation and wildlife. Section 69-5001, R.C.M.1947. Here it is admitted that no such problems existed with respect to relator’s certificate of survey. Rather, the sole reason for MDH’s refusal to process relator’s certificate of survey was its reliance on the invalid DCA regulations.

A writ of mandate “may be issued * * * to compel the performance of an act which the law specially enjoins as a duty resulting from an office, trust or station * * Section 93-9102, R.C.M.1947. The writ will issue only where the person seeking to invoke it is entitled to have the defendant perform a clear legal duty and there is no speedy or adequate remedy in the ordinary course of law. State ex rel. Kennedy v. Dist. Ct., 121 Mont. 320, 194 P.2d 256, 2 A.L.R.2d 1050.

Here there was a clear legal duty the defendants were required to perform for the reasons heretofore stated. A declaratory judgment action would not necessarily get the certificate of survey filed in the light of previous difficulties between petitioner and the clerk and recorder in getting such certificates filed as evi *310 denced in State ex rel. Swart v. Stucky, supra. A declaratory judgment action would not make petitioner whole as attorney fees are not allowable in such an action. A writ of mandate is the only remedy available to secure the ultimate relief sought by petitioner — to compel the lifting of sanitary restrictions, the filing of the certificate of survey, and an award of relator’s attorney fees.

The award of attorney fees and costs solely against DCA is proper. The void DCA regulations are the root of relator’s difficulties here. Accordingly, the assessment of attorney fees and costs entirely against DCA is justifiable.

We award additional attorney fees and expenses on appeal to relator solely against DCA in the amount of $973 as itemized in the affidavit filed herewith.

The judgment of the district court is affirmed.

MR. CHIEF JUSTICE HATFIELD and JUSTICES DALY, HARRISON and SHEA concur.