delivered the opinion of the Court.
The petitioners, James G. Brown et al., are the owners and operators of a producing oil and gas lease on lands owned by the respondent-lessor, Martha Lundell. The respondents in this suit allege that Brown disposed of the salt water produced from their well into an open pit and negligently allowed the same to percolate and seep into the subsurface stratum so as to pollute the underground water supply, thus permanently impairing the value of the land.
The jury found that Brown was negligent in permitting the salt water to escape from the disposal pit and in failing to protect the fresh water stratum and that such negligence was the proximate cause of the pollution complained of. The jury further found that the pollution is permanent. Judgment on the verdict was rendered in favor of lessor in the amount of the difference between the before and after values. The Court of Civil Appeals has affirmed. 334 S.W. 2d 616. We conclude that this judgment should not be disturbed.
It is Brown's position that the owner and operator of an oil and gas lease has the right to use so much of the premises and in such manner as is reasonably necessary to comply with the terms and purposes of the lease; that the use made of the premises was so confined and thus he had breached no duty to the lessor. Brown insists (1) that he had the right to produce and necessarily separate the oil from the water and dispose of the salt water in the earthen pit without incurring the burdensome expense of furnishing and using steel tanks or drilling a deep imput well; (2) that he had specially bought from the respondent landowner the right to use the land for the main*86tenance of the pit into which the salt water was deposited; and lessor had consented to let the premises for that use and was therefore precluded from recovering damages; (3) that he had disposed of the salt water in accordance with the uniform custom in that field and there was no proof that the custom itself was negligence; (4) that there was no proof of negligence or foreseeability.
First of all Brown complains that the Court of Civil Appeals sustained the judgment of the trial court on the theory that he was guilty of wanton conduct in the disposal of the salt water and the resultant damage.
While that court does attempt to differentiate between intentional and wilful on the one hand and wanton acts on the other and seems to predicate liability on that character of conduct, actually the case was pleaded and founded on negligence and not on the theory that the conduct of Brown was intentional, wilful or wanton. The jury found that Brown was negligent in the disposal of the salt water and judgment was rendered accordingly. The effect of the decision of the Court of Civil Appeals, regardless of what was said in the opinion, could only be an affirmance of the judgment rendered below predicated on negligent conduct.
We agree that the owner-operator of the lease has the right to use so much of the land, both surface and subsurface, as is reasonably necessary to comply with the terms of the lease contract and to carry out the purposes and intentions of the parties. Warren Petroleum Corp. v. Monzingo, 157 Texas 479, 304 S.W. 2d 362, 65 A.L.R. 2d 1352. It does not follow, however, that the operator may use either the surface or the subsurface in a negligent manner so as to damage the landowner. The lessor does not here seek to be paid for the use of more land than was necessary but rather her claim is predicated on the negligent use of the land.
While we did say in Warren Petroleum Corp. v. Martin, 153 Texas 465, 271 S.W. 2d 410, at 412, that the only duty owed by the lessee to the lessor was not to intentionally, wilfully or wantony injure his cattle, that rule is not applicable to the facts in the case before us. Some oil had escaped from the oil-well pump and accumuated in two small pools within five feet of the well. Lessor’s cattle died as a result of drinking the oil. We said in that case that, “the mere fact that petitioner permitted oil *87to escape and [collect on the ground within a few] feet of the well, without any showing as to the manner in which the lease was being operated at the time, could not form the basis for a legal inference that such conduct constituted negligence.”
We further held that since the lessee was the owner of the dominant estate he had the right to use so much of the premises as was reasonably necessary to the exclusion of the lessor in order to carry out the purposes of the mineral grant, but even so that right must be reasonably exercised with due regard to the rights of the owner of the surface.
Hence the decision in Warren v. Martin was based on two theories, (1) there was no proof of negligence; (2) the lessee was under no duty to exclude the cattle from the vicinity of the well and therefore the lessee owed no duty to the lessor except to refrain from intentional or wanton injury to his livestock. This case cannot be construed to hold that the operator is not liable for negligence in the disposal of salt water or that he is only liable for wilful and wanton pollution.
The right of the lessee in exploring for and producing oil and gas embraces only the doing of those things expressly granted or necessarily implied in the lease as necessarily incidental thereto. All property rights not granted are reserved in the lessor. The rights of the lessor and lessee are reciprocal and distinct. If either party exceeds those rights he becomes a trespasser. Gregg v. Caldwell-Guadalupe Pick Up Stations, Tex. Comm. App., 286 S.W. 1083. Thus, if the lessee negligently and unnecessarily damages the lessor’s land, either surface or subsurface, his liability to the lessor is no different from what it would be under the same circumstances to an adjoining landowner. The jury impliedly found that by taking reasonable precautions to dispose of the salt water that was accumulated as a necessary incident to the production of oil the operator could have avoided the pollution of the water. The operator did not obtain the right to permit the salt to drain and seep down into the subsoil and the resultant damage. The use of the lessor’s land is limited. In other words the lessor has granted and leased to the lessee only so much of his land as will be reasonably necessary to effectuate the purpose of the lease, and to be used in a non-negligent manner.
Brown cites other cases such as Sinclair Prairie Oil Co. v. Perry, Tex. Civ. App., 191 S.W. 2d 484, and Trinity Produce Co. *88v. Bennett, Tex. Civ. App., 258 S.W. 2d 160,1 where damages were sought for the loss of cattle resulting from drinking oily water around the oil well. Each of these cases hold that the operator is under no legal duty to fence off the well area where the oil and water had accumulated and that, so long as he uses the premises in the usual and customary manner consistent with the purposes and provisions of the lease, he would not be liable in damages merely because he failed to prevent the entry of the livestock on the premises. The import of those decisions is that even though the operator negligently allowed oil to accumulate on the ground around the well, he would not be liable in such a ease. Brown here argues that the rule is applicable to the facts of his case, namely, that he used the premises in the usual and customary manner and cannot be held in damages for negligence in allowing the salt water to percolate and pollute the subterranean waters; that he is no more liable for negligence in this case than he would be in a suit brought for damages where cattle had wandered in upon the premises and had drunk the salt water in the disposal pit.
We think the analogy is not sound. Rather the situation we have here is no different to the case where a lessee had negligently permitted the salt water to escape from his pit and flow over the lessor’s fields and damage the land and the growing crops. The distinction is that the lessee is entitled to use the land immediately surrounding the well reasonably necessary for his operations including such installations as tanks and slush pits. It was necessarily incident to production operations here that the salt water be separated from the oil and that it be disposed of, but the seepage of the salt into the fresh water stratum could have been prevented and constituted a negligent use of the premises.
In this connection lessee cites Texas Company v. Daugherty, 107 Texas 226, 176 S.W. 717, L.R.A. 1917 F, 989, and Guffey v. Stroud, 16 S.W. 2d 527, 64 A.L.R. 730 Comm. App. opinion adopted, for the proposition that lessee’s right of user extends to the entire premises. He quotes from Daugherty as follows:
“For the purpose of making the exploration and producing all the oil, gas and other minerals that might be within the ground, and the erection of all structures necessary thereto, as well as their storing and transportation, the possession of the land itself is likewise granted, with no limitation *89upon the number of wells or shafts that the grantee might sink, or the extent of its operations in that connection, and consequently no qualification of its right of possession to all such parts of the surface, except that no well should be drilled nearer than 200 feet from the house or barn on the premises without the consent of both parties, as might be necessary to its full use by the grantee for the purposes named.”
In that case the only point decided is that an oil and gas lease constitutes property subject to taxation. However, the court is not saying in the quoted paragraph that the possession of all the land leased is necessarily granted to the lessee to the exclusion of the lessor, but merely that the lessee has the exclusive right of possession and use of all or any part of the land necessary for exploration and production of oil and gas.
Guffey employs this language:
“The grant of the oil carried with it a grant of the way, surface, soil, water, gas and the like essential to the enjoyment of the actual grant of the oil.”
Thus, says the lessee, his right of user extends to the subsurface water. We do not question that proposition but the right to use does not imply the right to damage negligently or unnecessarily.
Brown offered proof that he had disposed of the salt water water in the earthen pit in accordance with the uniform practice and custom of the operators in that field. On the trial he requested an issue as to that fact and also one inquiring as to whether that custom was negligent. He complains of the trial court’s refusal to include those issues in the charge. He contends that where it is shown that he conducted his business in accordance with a uniform custom the lessor, in order to recover damages, must prove that the custom was negligent.
The trial judge, as to that matter, gave the following instruction to the jury:
“In connection with this definition of ‘negligence’ and ‘ordinary care,’ you are instructed that while compliance with a custom or conformity with usual and ordinary practices is not an absolute test of freedom from negligence, you may *90nevertheless properly consider the usual and customary practices of other operators engaged in the same or similar business and whether the defendant complied therewith, m determining whether the defendant was guilty of negligence.”
This sufficiently called the jury’s attention to the evidence on that score and the lessee could legitimately demand no more. The ultimate issue was whether Brown was negligent in the way and manner in which he disposed of the salt water, while the questions as to what was the custom, whether Brown had complied therewith and whether the custom itself was negligent, are only evidentiary as to the negligence of the operator. We are aware of no authorities to the contrary. In passing upon the admissibility of certain “custom” evidence, Hubb Diggs Co. v. Bell, Tex. Comm. App., 1 S.W. 2d 575, 576, holds as follows: “Whenever that kind of evidence is competent, conformity with the usage is some proof of due care, etc., and non-conformity, perforce, has an equal quantum of proof of negligence.” Admittedly custom is not an absolute test of negligence for the custom itself may be negligent. Evidence of custom is pertinent as an aid merely in determining the fact issue of negligence vel non on the part of the operator and to enable the Court or the jury to evaluate the operator’s conduct as compared to that of an ordinarily prudent operator. Comanche Duke Oil Co. v. Texas Pacific Coal & Oil Co., Texas Comm. App., 298 S.W. 554; Gulf C. & S. F. Ry. Co. v. Evansich, 61 Texas 3.
In support of his contention that the trial court should have submitted to the jury an issue inquiring as to whether or not the custom itself was negligent, Brown cites Taylor v. White, 212 S.W. 656, Texas Comm. App. (opinion adopted); Houston & T. C. R. Co. v. Werline, Tex. Civ. App., 84 S.W. 2d 288, wr. er. dism., and Chisos Mining Co. v. Hernandez, Tex. Civ. App., 96 S.W. 2d 292, wr. er. dism. In our opinion these decisions do not stand for that proposition. In the first case the trial court directed a verdict for the defendant. The negligence alleged consisted in the failure of the defendant to fix a guard rail around a certain machine and in placing a wrench on the floor over which the plaintiff stumbled and fell against the machine. The Commission of Appeals affirmed on the ground that the evidence was not sufficient to show that the defendant was guilty of negligence in failing to provide a guard rail, holding:
“The evidence without controversy shows that exciters *91of like kind were in general use throughout the country, and that no guard rails were provided in any of the plants using these machines to protect the employees. The custom of others engaged in like business is not the absolute test of negligence, but where the undisputed evidence shows affirmatively, as it does in this case, that the defendant was conducting his business in accordance with the uniform custom of persons engaged in like business, it devolves upon the plaintiff, before he can recover, to produce evidence showing that such custom is negligent. In the absence of such testimony, the legal presumption is that those engaged in like business were reasonably prudent in the conduct of their business, and that they discharged their legal obligations for the safety of their servants. Houston & T. C. Railway Co. v. Alexander, 103 Tex. 594, 132 S.W. 119; Canadian Northern Railway Co. v. Senske, 201 Fed. 637, 120 CCA 65.”
The court is not saying that the proper jury issue should have been one inquiring as to whether the custom was negligent but that since there was no evidence that the custom was negligent the defendant was guilty of no negligence. The court further observed that the wrench was placed on the floor by a fellow servant of plaintiff who was assisting him in his work and he could not recover therefor since he assumed the risk caused by the negligence of his fellow servants.
Houston & T. C. R. Co. v. Werline is generally to the same effect. In this case the plaintiff as a result of a seizure of some kind fell to the floor of the car unconscious and was burned as a result of her leg coming in contact with heated pipes under the forward seat. The basis of the reversal was that the situation was unanticipated and the resultant injury could not have been reasonably foreseen.
In Chisos Mining Co. v. Hernandez, the plaintiff pleaded negligence bn the part of his employer in failing to provide him with a safe place to work. The Court of Civil Appeals reversed and remanded on the ground that while the employer must exercise ordinary care to furnish his employee with a reasonably safe place to work that rule does not apply where the place, in this case, a mining shaft, becomes unsafe during the progress of the work. The comment we have made on the Taylor v. White opinion is applicable to this case.
Brown also cites our recent opinion in Texas & Pacific Ry. *92Co. v. Van Zandt, 159 Texas 178, 317 S.W. 2d 528. In that case the railroad company admitted negligence and defended solely on the contention that the plaintiff under the circujmstances did not and could not have sustained any personal injury whatever. So that there was submitted to the jury only the question of damages. While impliedly the inquiry as to injury was included in the damages issue, we said that under the circumstances the trial court should have submitted the sole defensive issue to the jury independently. This holding has no application here. The vital defense in our case was “no negligence” on the part of the operator. That issue was submitted.
For another reason Brown maintains that the lessor cannot recover. This contention is grounded upon payment of consideration to the lessor for the use of her land in the construction and maintenance of the earthen pit for the disposal of salt water. Lessee claims that the acceptance of the consideration and the written consent for the earthen pit forecloses her recovery and states the applicable rule to be “it is a well recognized maxim of the law that a person cannot recover for the consequences of an act which he himself has procured or consented to,” citing 1 C. J. 971, § 65. (1 C.J.S., Actions, § 23). Worded somewhat differently in 1 Am. Jur. § 17, p. 415: “It is a general rule that one cannot maintain an action for a wrong occasioned by an act to which he has consented, under the familiar maxim, ‘volenti non fit injuria,’ * *
The operator says that, since the lessor consented to the construction of the earthen pit, knowing that the salt water and other waste would be deposited in it and accepted payment for that use of the premises, she cannot recover and the operator is not to be held guilty of negligence in exercising the right that was granted. This argument, like the disposal pit, will not hold water. What Brown failed to allege and prove is that the lessor had reason to know or to be aware that the salt water would probably percolate downward and pollute the fresh water supply. If that had been shown as a fact then equitable estoppel might be employed against her claim for damages and the foregoing rule brought into play. We think that the fact that Brown paid for the privilege of constructing and using an earthen pit will avail him nothing. Under the rule that he had the right to use so much of the land as was reasonably necessary in the production of oil and since the production of oil necessarily involved its separation from the salt water, he would have had the right, ordinarily under the implied terms of the lease, to use the land for that purpose without paying any additional compensation.
*93Brown invokes the familiar maxim of “volenti non fit injuria” and seeks to apply the rule to the present situation. This doctrine can have no application to the facts developed in this case. The lessor did know that the salt water would be deposited in the earthen tank and consented thereto. It does not follow, however, that she thereby gave her consent for the salt water to percolate into the subterranean fresh water stratum. For the doctrine of “volenti non fit injuria” to apply she must not only have known that the salt water would be deposited in the pit but also that such a great quantity of salt and salt waiter disposed of in the pit would probably pollute and contaminate the underground water. It is not shown that she had any such knowledge. Brown did request an issue as to whether the lessor had consented to the disposal of salt water in the disposal or burning pit, and complains of the trial court’s refusal of that issue. This ruling was not erroneous. We think unquestionably she did so consent but no further issue was requested as to whether she was aware of the probable pollution. The doctrine of “volenti non fit injuria” presupposes a knowledge of the facts so that the actor has a choice. Schiller v. Rice, 151 Texas 116, 246 S.W. 2d 607. In this case it cannot be said that the lessor assumed a known and appreciated risk. See also Triangle Motors of Dallas v. Richmond, 152 Texas 354, 258 S.W. 2d 60.
McCue v. Klein, 60 Texas 168, in speaking of this maxim, says it presupposes that the party is capable of giving assent to his own injury, and “If he is divested of the power of refusal by reason of total or partial want of mental faculties, the damage cannot be excused on the ground of consent given.” The court goes on to say that lack of knowledge of the danger will not afford excusable consent.
The correspondence in regard to this cash payment to lessor clearly shows that it was given in consideration for the use of land around the well on the acreage basis, being one and one-half acres at $600.00 per acre. Additionally, the lessor was paid $400.00 “to cover anticipated surface damage for ground slush pit.” This does not afford any inference that Brown bought the right to permit the salt and salt water to escape from the pit and damage either the surface or the subsurface of lessor’s land.2
*94We cannot agree with petitioner that the record discloses no evidence of negligence on his part or no evidence of foreseeability. Within the space of 15 months after production was obtained lessee poured some 3,000,000 gallons of salt water into this earthen tank. The analysis showed that this volume of water contained a total of nearly 4,000 tons of salt exclusive of other solids. It was undisputed that seepage of this salt water caused the pollution complained of. When complaint of this pollution was made by the landowner the petitioner proimptly converted one of his smaller producing wells into an “input” well and injected the salt water back into its original stratum. The petitioner himsef testified that if he had thought seriously about the possibility of pollution he would have tried to devise another system of disposal. He knew or should have known of the amount of water that was being placed in the pit and of its salt content ; that in an open, unsealed tank that some of the water would evaporate, some would normally percolate and seep into the ground. He knew that no salt deposits had ever been removed from the pit. There was testimony indicating that there had been complaint of salt water pollution from open disposal pits in other sections of this general area and other producers had switched to the reinjection method previously. Brown knew that a fresh water formation underlay this farm and that this water was used for irrigation and farming purposes. The cubic dimensions of this disposal pit are not shown in the record so far as we know, but from photographs taken presumably after cessation of its use, the jury could reach some approximation of its capacity and size.
The lessee says there is no evidence in this case establishing negligence “in the usual sense” and that proof of specific acts of negligence is required as a basis for pollution damages caused by oil and gas production wastes. In support of that proposition he cites our holding in Turner v. Big Lake Oil Co., 128 Texas 155, 96 S.W. 2d 221, namely that the mere fact, that salt water had escaped from disposal pits and contaminated the adjoining land, was not in itself proof of negligence, but in order for plaintiffs to recover they must allege and prove some specific acts of negligence. The question presented in that case was whether or not the operator was to be held as an insurer or whether the cause of action must be predicated on negligence. Four issues of negligence were submitted to the jury, all being found adversely to the landowner. The holding of the court, simply stated, is that the lessee may not be held liable in damages for injury to property occasioned by the escape of salt water *95from pits constructed and used by him in the operation of his oil wells without proof of negligence on his part. From what is said in the opinion it is not unreasonable to conclude that but for the unfavorable findings of the jury the landowner would have been entitled to a recovery. We do not understand that lessee either in the Court of Civil Appeals or here has complained of the form of the issues submitted by the trial court.
In Pickens v. Harrison, 151 Texas 562, 252 S.W. 2d 575, the facts seem to be no more compelling as to negligence and foreseeability than they are here. In that case the operator had disposed of some 200,000 gallons of salt water into a pit about 25 x 25 feet square and 13 feet deep during the ten days of its use and yet the “no evidence” assignments were overruled. See also Gulf Oil Corp. v. Bob Alexander, 291 S.W. 2d 792, wr. ref. n.r.e., 156 Texas 455, 295 S.W. 2d 901.
The last point urged by petitioner relates to the refusal of the court of a motion for discovery and inspection under Rule 167, Rules of Civil Procedure. By this motion he sought authority to drill a water well on the eastern part of respondent’s land to test the water under that portion of the property. He contends that the driling of such a well would have proved beyond any doubt that good water could be had on that portion of the farm and thus would materially affect the market value of the property. This well could have been drilled and the water tested within a period of two weeks. It was the position of the lessor that a well drilled in the eastern portion of the farm at that time would show that the water was not contaminated but that after a period of excessive pumping it might possibly become polluted from the salt water theretofore disposed of in the pit. It appears that this suit was filed on February 14, 1958. The motion was filed January 20, 1959. It was presented and overruled on the 24th day of January, 1959. The case went to trial on February 10, 1959.
The lessor’s expert witness, a ground water engineer and geologist, testified on the trial that a water well drilled at that time in the northeastern portion of lessor’s property would not show polluted water and even though pumped would not draw in any contaminated water for a considerable length of time. Thus it would seem that lessor substantially admitted everything that the operator sought to prove by the drilling of a well. The action of the trial court upon this motion was within his sound discretion and is to be overturned only upon a showing of an *96abuse of that discretion. Crane v. Tunks, 160 Texas 182, 328 S.W. 2d 434. In View of the circumstances there is shown no abuse of discretion on the part of the trial court.
The judgments of the Court of Civil Appeals and district court are both affirmed.
Steakley, Judge, not sitting.
No application for writ of error applied for in either case.
The lease provides: “Lessee shall pay to Martha Lundell individually the sum of $600.00 per acre for each acre of said land used by lessee for his operations hereunder, including the acreage used by roads, tanks, drill sites, or for any other purpose.”