Halacha

הלכה א
מַעֲלוֹת יְתֵרוֹת עָשׂוּ בְּטָהֳרַת הַחַטָּאת. שֶׁהָאָדָם הַטָּהוֹר אֲפִלּוּ טָבַל לְקֹדֶשׁ וְעוֹמֵד וּמְשַׁמֵּשׁ עַל גַּבֵּי הַמִּזְבֵּחַ אֵינוֹ טָהוֹר לְחַטָּאת וְלֹא לִשְׂרֵפַת הַפָּרָה וְלֹא לְמִלּוּי הַמַּיִם וְלֹא לְקַדְּשָׁן וְלֹא לְהַזּוֹת עַד שֶׁיִּטְבּל לְשֵׁם חַטָּאת וְאַחַר כָּךְ יִהְיֶה טָהוֹר לְחַטָּאת. וְכֵן הַכֵּלִים אֲפִלּוּ מִזְרָק שֶׁבָּעֲזָרָה אֵינוֹ טָהוֹר לְחַטָּאת עַד שֶׁיַּטְבִּילוּהוּ לְשֵׁם חַטָּאת. וְכֵן כָּל הָאֳכָלִין וְכָל הַמַּשְׁקִין אַף עַל פִּי שֶׁהֵן טְהוֹרִין הֲרֵי הֵן לְעִנְיַן חַטָּאת כָּאֳכָלִין וּמַשְׁקִין הַמְטַמְּאִין:
כסף משנה
1.
Extra stringencies were instituted with regard to the purification process involving the ashes of the red heifer. A person who was pure - even if he immersed himself in a mikveh for the sake of sacrificial service and stood and served on the altar - is not pure with regard to the purification process involving the ashes of the red heifer, nor with regard to the burning of the red heifer, drawing its water, sanctifying it, or sprinkling it unless he immerses himself for the sake of the purification process involving the ashes of the red heifer. Afterwards, he is considered pure for that purpose.
Similarly, keilim - even a receptacle taken from the Temple Courtyard - are not considered as pure with regard to the purification process involving the ashes of the red heifer unless they were immersed for that purpose. Similarly, all foods and liquids - even if they are pure - are considered as impure in this context.

הלכה ב
כָּל כְּלִי הָרָאוּי לְמִשְׁכָּב אוֹ לְמוֹשָׁב אַף עַל פִּי שֶׁהוּא טָהוֹר לְגַבֵּי הַקֹּדֶשׁ הֲרֵי הוּא לְגַבֵּי חַטָּאת כְּמִדְרַס הַזָּב עַד שֶׁיַּטְבִּילוּהוּ לְשֵׁם חַטָּאת. יוֹחָנָן בֶּן גֻּדְגְּדָא הָיָה אוֹכֵל בְּטָהֳרַת הַקֹּדֶשׁ כָּל יָמָיו וְהָיָה מִטְפַּחְתּוֹ כְּמִדְרַס הַזָּב לְעִנְיַן הַחַטָּאת:
כסף משנה
2.
Any entity that is fit to lie on or sit on, even though it is pure with regard to sacrificial foods is considered like an entity to which a zav imparted impurity with regard to the purification process involving the ashes of the red heifer until it was immersed with that intent in mind. Yochanan ben Gudgada would always eat according to the strictures of ritual purity required for sacrificial foods. Yet his head cloth was like an entity to which a zav imparted impurity with regard to the purification process involving the ashes of the red heifer.

הלכה ג
כָּל וְלַד הַטֻּמְאוֹת אַף עַל פִּי שֶׁאֵינוֹ מְטַמֵּא אָדָם וְלֹא כֵלִים אֲפִלּוּ לְקֹדֶשׁ כְּמוֹ שֶׁבֵּאַרְנוּ. הֲרֵי הוּא מְטַמֵּא אָדָם וְכֵלִים לְחַטָּאת. לְפִיכָךְ אָמְרוּ הַמְקַדֵּשׁ אֶת מֵי חַטָּאת לֹא יִנְעל אֶת הַסַּנְדָּל. שֶׁמָּא יִפְּלוּ מַשְׁקִין עַל הַסַּנְדָּל וְנִמְצָא הַסַּנְדָּל טָמֵא שֶׁכָּל הַמַּשְׁקִין טְמֵאִין הֵן לִגבֵּי החטָּאת וִיתִטמֵּא זֶה הַמְקַדֵּשׁ בִּנְגִיעָתוֹ בְּסַנְדָּל וְנִמְצְאוּ מֵי חַטָּאת טְמֵאִים:
כסף משנה
3.
A derivative of impurity does not impart impurity to a person or to a k'li, even with regard to sacrificial articles, as we explained. Nevertheless, it imparts impurity to persons and keilim with regard to the purification process involving the ashes of the red heifer. Therefore it was said that a person who sanctifies the water used for the purification process should not wear a sandal, lest liquids fall on the sandal and the sandal contract impurity. The rationale is that all liquids are considered as impure with regard to the purification process involving the ashes of the red heifer. Then the person sanctifying the water will contract impurity by touching the sandal and thus the purifying water will become impure.

הלכה ד
מִי שֶׁנִּטְמְאוּ יָדָיו בִּלְבַד בַּדְּבָרִים הַמְטַמְּאִין אֶת הַיָּדַיִם כְּגוֹן שֶׁנָּגַע בָּאֳכָלִין אוֹ בְּמַשְׁקִין וְכַיּוֹצֵא בָּהֶן אַף עַל פִּי שֶׁהוּא טָהוֹר לַקֹּדֶשׁ וְאֵינוֹ צָרִיךְ אֶלָּא טְבִילַת יָדָיו בִּלְבַד כְּמוֹ שֶׁיִּתְבָּאֵר. הֲרֵי נִטְמָא כָּל גּוּפוֹ לְעִנְיַן הַחַטָּאת וְצָרִיךְ טְבִילָה. אֲפִלּוּ לֹא נִטְמֵאת אֶלָּא יָדוֹ אַחַת נִטְמָא כֻּלּוֹ וַהֲרֵי הוּא רִאשׁוֹן לְטֻמְאָה:
כסף משנה
4.
When only a person's hands become impure due to causes that render hands impure, e.g., he touched foods or liquids or the like, although he is considered as pure with regard to sacrificial food, and all that is necessary is that he wash his hands as will be explained, with regard to the purification process involving the ashes of the red heifer, his entire body is considered to have contracted impurity and he must immerse in a mikveh. Even if only one hand contracted impurity, it is as if his entire body contracted impurity. He is considered as impure to the first degree.

הלכה ה
כָּל הַטָּעוּן טְבִילָה בֵּין מִן הַתּוֹרָה בֵּין מִדִּבְרֵיהֶם מְטַמֵּא אֶת מֵי חַטָּאת וְאֶת אֵפֶר הַחַטָּאת וְאֶת הַמַּזֶּה מֵי חַטָּאת בְּמַגָּע וּבְמַשָּׂא. וְכֵן מְטַמֵּא אֶת הָאֵזוֹב הַמֻּכְשָׁר וְאֶת הַמַּיִם שֶׁנִּתְמַלְּאוּ וַעֲדַיִן לֹא נִתְקַדְּשׁוּ. וְאֶת הַכְּלִי הָרֵיקָן הַטָּהוֹר לְחַטָּאת. מְטַמֵּא כָּל אֶחָד מֵאֵלּוּ בְּמַגָּע אֲבָל לֹא בְּמַשָּׂא. וְטָמֵא שֶׁנָּגַע בְּמִקְצָת אֵפֶר חַטָּאת פָּסַל אֶת כֻּלּוֹ:
כסף משנה
5.
Any person who is required to be immersed in a mikveh, whether according to Scriptural Law or Rabbinic Law, imparts impurity to the water sanctified with the ashes of the red heifer, the ashes themselves, and the one who sprinkles them, through touching or carrying them. Similarly, he imparts impurity to a hyssop that has been made fit to contract impurity, water that has been drawn for this process but has not yet been sanctified, and an empty container that has been purified for this purification process. The latter three entities contract impurity only through touch, but not through being carried.
When an impure person touches a small portion of ashes of the red heifer, it is considered as if he touched all of them.

הלכה ו
אֵין מוֹנִין לְחַטָּאת רִאשׁוֹן וְשֵׁנִי וּשְׁלִישִׁי כְּדֶרֶךְ שֶׁמּוֹנִין לִתְרוּמָה וּלְקֹדֶשׁ. כֵּיצַד. עֲשָׂרָה שֶׁטָּבְלוּ לְשֵׁם חַטָּאת וְנִטְמָא אֶחָד מֵהֶן אֲפִלּוּ לֹא נִטְמָא אֶלָּא לְגַבֵּי חַטָּאת בִּלְבַד כְּגוֹן שֶׁנִּטְמֵאת יָדוֹ בִּלְבַד וְנָגַע בַּחֲבֵרוֹ וַחֲבֵרוֹ בַּחֲבֵרוֹ אֲפִלּוּ הֵן מֵאָה כֻּלָּן טְמֵאִין לְחַטָּאת. וְכֵן כֵלִים הַטְּהוֹרִים לְחַטָּאת שֶׁנִּטְמָא כְּלִי מֵהֶן אֲפִלּוּ לֹא נִטְמְאוּ אֶלָּא אֲחוֹרָיו בִּלְבַד לְגַבֵּי חַטָּאת כְּגוֹן שֶׁנָּגְעוּ מַשְׁקִין בַּאֲחוֹרָיו וְנָגַע כְּלִי זֶה בִּכְלִי שֵׁנִי וְשֵׁנִי בִּשְׁלִישִׁי נִטְמְאוּ הַכֵּלִים כֻּלָּן לְגַבֵּי הַחַטָּאת וַאֲפִלּוּ הֵן מֵאָה:
כסף משנה
6.
Primary, secondary, and tertiary levels of impurity are not counted with regard to the purification process involving the ashes of the red heifer as are counted with regard to terumah and sacrificial foods.
What is implied? If there were ten persons who immersed themselves for the sake of this purification process and one became impure, even if he became impure only with regard to this purification process, e.g., his hands became impure, should he touch a colleague and that colleague touch another, and that one another, even if there are 100, they all become impure with regard to this purification process.
Similarly, when there are keilim that were purified for this purification process and one of them contracted impurity - even if only its outside contracted impurity for this purification process, e.g., liquids touched its outside - and this k'li touched a second k'li and the second touched a third, all of the keilim, even if there are 100, become impure with regard to this purification process.

הלכה ז
כָּל הָרָאוּי לְהִתְטַמֵּא בְּמִדְרַס הַזָּב אַף עַל פִּי שֶׁהוּא טָהוֹר לְקֹדֶשׁ אִם הֵנִידוֹ הַטָּהוֹר לְחַטָּאת נִטְמָא אַף עַל פִּי שֶׁלֹּא נָגַע בּוֹ. וְכֵן הַטָּהוֹר לְחַטָּאת שֶׁהֵנִיד אֶת הָאָדָם שֶׁאֵינוֹ טָהוֹר לְחַטָּאת. אוֹ שֶׁהֵנִיד אֶת רֻקּוֹ אוֹ אֶת מֵימֵי רַגְלָיו שֶׁל אָדָם זֶה. נִטְמָא אַף עַל פִּי שֶׁלֹּא נָגַע בּוֹ. אֲבָל כְּלִי שֶׁאֵינוֹ רָאוּי לְמִדְרָס אֵינוֹ מְטַמֵּא אֶת הַטָּהוֹר לְחַטָּאת אֶלָּא אִם כֵּן נָגַע בּוֹ:
כסף משנה
7.
Whenever an article that is fit to contract impurity if it would support a zav - even though it is pure with regard to sacrificial foods - was moved by a person who purified himself for the sake of this purification process, he contracts impurity, even though he did not touch it.
Similarly, when a person who purified himself for the sake of this purification process moves a person who is not pure in this context or he moves the spittle or the urine of the latter person, he becomes impure, even though he did not touch him. A k'li that is not fit to contract impurity if it would support a zav, by contrast, does not impart impurity to a person who has purified himself for the sake of this purification process unless he touches it.

הלכה ח
כְּלִי הַטָּמֵא בִּטְמֵא מֵת אִם הֵנִידוֹ הַטָּהוֹר לְחַטָּאת נִטְמָא וְאַף עַל פִּי שֶׁלֹּא נָגַע בּוֹ וְאַף עַל פִּי שֶׁאֵין טְמֵא מֵת מְטַמֵּא בְּמַשָּׂא כְּמוֹ שֶׁבֵּאַרְנוּ. כֵּיצַד. מַפְתֵּחַ שֶׁהוּא טְמֵא מֵת שֶׁהָיָה תָּלוּי בַּדֶּלֶת וְסָגַר הַטָּהוֹר לְחַטָּאת אֶת הַדֶּלֶת הוֹאִיל וְהֵנִיד אֶת הַמַּפְתֵּחַ הַטָּמֵא נִטְמָא. וְכֵן אִם הֵסִיט אֶת הַשֶּׁרֶץ וְאֶת שִׁכְבַת זֶרַע הֲרֵי זֶה טָמֵא לְחַטָּאת אַף עַל פִּי שֶׁאֵין אֵלּוּ מְטַמְּאִין בְּמַשָּׂא כְּמוֹ שֶׁיִּתְבָּאֵר:
כסף משנה
8.
If a k'li that is impure because of contact with a human corpse is moved by a person who has purified himself for the purification process involving the ashes of the red heifer, he becomes impure even though he did not touch it and even though generally an article that is impure because of contact with a corpse does not impart impurity when carried, as we explained.
What is implied? There was a key that was impure due to contact with a corpse that was hanging from a door. A person who purified himself for this purification process closed the door. Since he moved the key which was impure, he himself contracts impurity. Similarly, if he moves the carcass of a crawling animal or semen, he becomes impure with regard to this purification process even though generally these do not impart impurity when carried, as will be explained.

הלכה ט
הַטָּהוֹר לְחַטָּאת שֶׁנָּגַע בְּכֵלִים שֶׁהָיוּ לְמַעְלָה מִן הַזָּב וְכַיּוֹצֵא בּוֹ וְהֵן הַנִּקְרָאִין מַדָּף אַף עַל פִּי שֶׁהוּא טָהוֹר לְקֹדֶשׁ נִטְמָא לְחַטָּאת. וְכֵן כְּלִי הַטָּהוֹר לְחַטָּאת שֶׁנָּגַע בְּמַדָּף נִטְמָא לְחַטָּאת:
כסף משנה
9.
When a person who purified himself for this purification process touches articles that were above a zav or the like, these are called madaf, he is considered impure with regard to this purification process, even though he is pure with regard to sacrificial foods. Similarly, when a k'li that was purified for this purification process touches a madaf, it contracts impurity with regard to this purification process.

הלכה י
הַטָּהוֹר לְחַטָּאת שֶׁנָּגַע בָּאֳכָלִין וּמַשְׁקִין בֵּין טְהוֹרִין בֵּין טְמֵאִים שֶׁכָּל אֳכָלִין וּמַשְׁקִין לְגַבֵּי חַטָּאת אֵינָן טְהוֹרִין אִם נָגַע בָּהֶן בְּיָדוֹ נִטְמָא כָּל גּוּפוֹ כְּמוֹ שֶׁבֵּאַרְנוּ. נָגַע בָּהֶן בְּרַגְלוֹ אוֹ בִּשְׁאָר גּוּפוֹ אוֹ שֶׁהֱסִיטָן בְּיָדוֹ וְלֹא נָגַע בָּהֶן טָהוֹר. וְכֵן אִם נָגַע בְּתַנּוּר וְכַיּוֹצֵא בּוֹ מִשְׁאָר כֵּלִים שֶׁאֵינָם טְהוֹרִין לְחַטָּאת נִטְמָא כֻּלּוֹ. אֲבָל אִם נָגַע בְּרַגְלוֹ בָּהֶן הֲרֵי הוּא טָהוֹר לְחַטָּאת כְּמוֹ שֶׁהָיָה:
כסף משנה
10.
The following laws apply when a person who purified himself for this purification process touches foods or liquids, whether impure or pure. No distinction is made between them, because there are no foods or liquids that are considered as pure with regard to this purification process.
If a person touches foods or liquids with his hands, his entire body becomes impure, as we explained. If he touches them with his foot or other portions of his body, or moves them with his hands without touching them, he remains pure. Similarly, if, with his hands, he touched an oven or the like, i.e., other articles that were not purified for the sake of this purification process, his entire body contracts impurity. If, however, he touches such articles with his feet, his status of purity remains unchanged, even with regard to this purification process.

הלכה יא
הַטָּהוֹר לְחַטָּאת שֶׁהִכְנִיס רֹאשׁוֹ וְרֻבּוֹ לְתוֹךְ מַיִם שֶׁנִּתְמַלְּאוּ לְחַטָּאת נִטְמָא מִפְּנֵי שֶׁהֵן שְׁאוּבִין. וּמִדִּבְרֵי סוֹפְרִים שֶׁהַבָּא רֹאשׁוֹ וְרֻבּוֹ בְּמַיִם שְׁאוּבִין נִטְמָא כְּמוֹ שֶׁיִּתְבָּאֵר:
כסף משנה
11.
When a person who purified himself for this purification process inserted his head and the majority of his body into water that was drawn for the sake of this purification process, he contracts impurity, because the water has been drawn. For it is a Rabbinical decree that anyone who inserts his head and the majority of his body into water that was drawn contracts impurity, as will be explained.

הלכה יב
הַכּל נֶאֱמָנִין עַל טָהֳרַת הַחַטָּאת וַאֲפִלּוּ עַמֵּי הָאָרֶץ מִפְּנֵי חֻמְרָתָהּ. וּמַעֲלוֹת אֵלּוּ שֶׁעָשׂוּ בָּהּ הַכּל נִזְהָרִין בָּהּ. וַהֲרֵי נֶאֱמַר בַּתּוֹרָה (במדבר יט ט) "וְהָיְתָה לַעֲדַת בְּנֵי יִשְׂרָאֵל לְמִשְׁמֶרֶת" כָּל יִשְׂרָאֵל רְאוּיִין לִשְׁמִירָה. לְפִיכָךְ עַם הָאָרֶץ שֶׁהֵבִיא כְּלִי מִבֵּיתוֹ אֲפִלּוּ כְּלִי חֶרֶס וְאָמַר כְּלִי זֶה טָהוֹר לְחַטָּאת הֲרֵי זֶה טָהוֹר וּמְקַדְּשִׁין בּוֹ וּמַזִּין מִמֶּנּוּ. וְאַף עַל פִּי שֶׁאוֹתוֹ כְּלִי טָמֵא לְקֹדֶשׁ וְלִתְרוּמָה. וְכֵן עַם הָאָרֶץ שֶׁאָמַר טָהוֹר אֲנִי לְחַטָּאת אוֹ שֶׁהָיוּ מֵי חַטָּאת אֶצְלוֹ וְאָמַר טְהוֹרִין הֵן נֶאֱמָן. שֶׁאֵין אָדָם מִיִּשְׂרָאֵל מְזַלְזֵל בָּהּ:
כסף משנה
12.
Everyone's word is accepted with regard to the ritual purity of articles and persons involved in this purification process, even that of the common people. The rationale is that because of all the stringencies and extra measures applied to it, everyone is careful with regard to it. This is alluded to in the Torah which states Numbers 19:9: "And it will be for the congregation of Israel for safekeeping." Implied is that all of Israel are fit for its safekeeping.
Therefore if a common person brings an earthenware container from his home and says: "This container is pure for the purification process involving the ashes of the red heifer," it is considered as pure. Water may be sanctified in it and sprinkled from it even though this container would be considered as impure for sacrificial foods and for terumah. Similarly, if a common person says: "I have purified myself for the purification process involving the ashes of the red heifer" or the water for this process was in his possession and he says that it is pure, his word is accepted. For no Jewish person treats this purification process lightly.

טהרה הלכות פרה אדומה פרק יג
Taharah Para Aduma Chapter 13